• There are no items in your cart

BS IEC 61508-6 : 2000 AMD 13784

Superseded
Superseded

A superseded Standard is one, which is fully replaced by another Standard, which is a new edition of the same Standard.

View Superseded by
superseded

A superseded Standard is one, which is fully replaced by another Standard, which is a new edition of the same Standard.

FUNCTIONAL SAFETY OF ELECTRICAL/ELECTRONIC/PROGRAMMABLE ELECTRONIC SAFETY-RELATED SYSTEMS - PART 6: GUIDELINES ON THE APPLICATION OF IEC 61508-2 AND IEC 61508-3
Superseded date

03-15-2002

Published date

11-23-2012

FOREWORD
INTRODUCTION
1 Scope
2 Normative references
3 Definitions and abbreviations
Annex A (informative) Application of IEC 61508-2 and of
                      IEC 61508-3
      A.1 - General
      A.2 - Functional steps in the application of
            IEC 61508-2
      A.3 - Functional steps in the application of
            IEC 61508-3
Annex B (informative) Example technique for evaluating
                      probabilities of hardware failure
      B.1 - General
      B.2 - Average probability of failure on demand (for
            low demand mode of operation)
      B.3 - Probability of failure per hour (for high demand
            or continuous mode of operation
      B.4 - References
Annex C (informative) Calculation of diagnostic coverage and
                      safe failure fraction: worked example
Annex D (informative) A methodology for quantifying the
                      effect of hardware-related common cause
                      failures in E/E/PE systems
      D.1 - General
      D.2 - Brief overview
      D.3 - Scope of the methodology
      D.4 - Points taken into account in the methodology
      D.5 - Using the beta-factor to calculate the
            probability of failure in an E/E/PE safety-
            related system due to common cause failures
      D.6 - Using the tables to estimate beta
      D.7 - Examples of the use of the methodology
      D.8 - References
Annex E (informative) Example applications of software safety
                      integrity tables of IEC 61508-3
      E.1 - General
      E.2 - Example for safety integrity level 2
      E.3 - Example for safety integrity level 3
Bibliography
Figure 1 - Overall framework of IEC 61508
Figure A.1 - Application of IEC 61508-2
Figure A.2 - Application of IEC 61508-2 (continued)
Figure A.3 - Application of IEC 61508-3
Figure B.1 - Example configuration for two sensor channels
Figure B.2 - Subsystem structure
Figure B.3 - 1oo1 physical block diagram
Figure B.4 - 1oo1 reliability block diagram
Figure B.5 - 1oo2 physical block diagram
Figure B.6 - 1oo2 reliability block diagram
Figure B.7 - 2oo2 physical block diagram
Figure B.8 - 2oo2 reliability block diagram
Figure B.9 - 1oo2D physical block diagram
Figure B.10 - 1oo2D reliability block diagram
Figure B.11 - 2oo3 physical block diagram
Figure B.12 - 2oo3 reliability block diagram
Figure B.13 - Architecture of an example for low demand mode
              of operation
Figure B.14 - Architecture of an example for high demand or
              continuous mode of operation
Figure D.1 - Relationship of common cause failures to the
             failures of individual channels
Table B.1 - Terms and their ranges used in this annex
            (applies to 1oo1, 1oo2, 2oo2, 1oo2D and 2oo3)
Table B.2 - Average probability of failure on demand for a
            proof test interval of six months and a mean time
            to restoration of 8 h
Table B.3 - Average probability of failure on demand for a
            proof-test interval of one year and mean time to
            restoration of 8 h
Table B.4 - Average probability of failure on demand for a
            proof-test interval of two years and mean time to
            restoration of 8 h
Table B.5 - Average probability of failure on demand for a
            proof-test interval of 10 years and mean time to
            restoration of 8 h
Table B.6 - Average probability of failure on demand for the
            sensor subsystem in the example for low demand
            mode of operation (one year proof-test interval
            and 8 h MTTR)
Table B.7 - Average probability of failure on demand for the
            logic subsystem in the example for low demand
            mode of operation (one year proof-test interval
            and 8 h MTTR)
Table B.8 - Average probability of failure on demand for the
            final element subsystem in the example for low
            demand mode of operation (one year proof-test
            interval and 8 h MTTR)
Table B.9 - Example for a non-perfect proof test
Table B.10 - Probability of failure per hour (in high demand
             or continuous mode of operation) for a proof-
             test interval of one month and a mean time to
             restoration of 8 h
Table B.11 - Probability of failure per hour (in high demand
             or continuous mode of operation) for a proof
             test interval of three months and a mean time to
             restoration of 8 h
Table B.12 - Probability of failure per hour (in high demand
             or continuous mode of operation) for a proof
             test interval of six months and a mean time to
             restoration of 8 h
Table B.13 - Probability of failure per hour (in high demand
             or continuous mode of operation) for a proof
             test interval of one year and a mean time to
             restoration of 8 h
Table B.14 - Probability of failure per hour for the sensor
             subsystem in the example for high demand or
             continuous mode of operation (six month proof-
             test interval and 8 h MTTR)
Table B.15 - Probability of failure per hour for the logic
             subsystem in the example for high demand or
             continuous mode of operation (six month proof-
             test interval and 8 h MTTR)
Table B.16 - Probability of failure per hour for the final
             element subsystem in the example for high demand
             or continuous mode of operation (six month
             proof-test interval and 8 h MTTR)
Table C.1 - Example calculations for diagnostic coverage and
            safe failure fraction
Table C.2 - Diagnostic coverage and effectiveness for
            different subsystems
Table D.1 - Scoring programmable electronics or sensors/final
            elements
Table D.2 - Value of Z: programmable electronics
Table D.3 - Value of Z: sensors or final elements
Table D.4 - Calculation of beta or betaD
Table D.5 - Example values for programmable electronics
Table E.1 - Software safety requirements specification (see
            7.2 of IEC 61508-3)
Table E.2 - Software design and development: software
            architecture design (see 7.4.3 of IEC 61508-3)
Table E.3 - Software design and development: support tools
            and programming language (see 7.4.4 OF (IEC
            61508-3)
Table E.4 - Software design and development: detailed design
            (see 7.4.5 and 7.4.6 of IEC 61508-3) (this
            includes software system design, software module
            design and coding)
Table E.5 - Software design and development: software module
            testing and integration (see 7.4.7 and 7.4.8 of
            IEC 61508-3)
Table E.6 - Programmable electronics integration (hardware
            and software) (see 7.5 of IEC 61508-3)
Table E.7 - Software safety validation (see 7.7 of IEC
            61508-3)
Table E.8 - Software modification (see 7.8 of IEC 61508-3)
Table E.9 - Software verification (see 7.9 of part 3)
Table E.10 - Functional safety assessment (see clause 8 of
             IEC 61508-3)
Table E.11 - Software safety requirements specification (see
             7.2 of IEC 61508-3)
Table E.12 - Software design and development: software
             architecture design (see 7.4.3 of IEC 61508-3)
Table E.13 - Software design and development: support tools
             and programming language (see 7.4.4 of IEC
             61508-3)
Table E.14 - Software design and development: detailed
             design (see 7.4.5 and 7.4.6 of IEC 61508-3)
             (this includes software system design, software
             module design and coding)
Table E.15 - Software design and development: software
             module testing and integration (see 7.4.7 and
             7.4.8 of IEC 61508-3)
Table E.16 - Programmable electronics integration (hardware
             and software) (see 7.5 of IEC 61508-3)
Table E.17 - Software safety validation (see 7.7 of IEC
             61508-3)
Table E.18 - Modification (see 7.8 of IEC 61508-3)
Table E.19 - Software verification (see 7.9 of IEC 61508-3)
Table E.20 - Functional safety assessment (see clause of IEC
             61508-3)

Provides guidelines and information on parts -2 an -3 of IEC 61508. Should be read in conjunction with certain sections of IEC 61508-2 and -3. Gives a brief outline of requirements of parts -2 and -3 of the standard, and sets out functional steps in their application. Covers an example technique to calculate probabilities of hardware failure, gives a worked example of calculating diagnostic coverage, gives a methodology for quantifying the effect of hardware-related common cause failures on the probability of failure, and gives worked exampleso of the application of the software safety integrity tables.

Committee
GEL/65
DevelopmentNote
Renumbered and Superseded by BS EN 61508-6. Supersedes 98/261465 DC (04/2002)
DocumentType
Standard
PublisherName
British Standards Institution
Status
Superseded
SupersededBy
Supersedes

Standards Relationship
IEC 61508-6:2010 Identical

ISO/IEC Guide 51:2014 Safety aspects Guidelines for their inclusion in standards
IEC GUIDE 104:2010 The preparation of safety publications and the use of basic safety publications and group safety publications

View more information
Sorry this product is not available in your region.

Access your standards online with a subscription

Features

  • Simple online access to standards, technical information and regulations.

  • Critical updates of standards and customisable alerts and notifications.

  • Multi-user online standards collection: secure, flexible and cost effective.