Reliability Prediction Method for Safety Instrumented Systems
PDS Method Handbook 2013 Edition
Forfattere: Stein Hauge, Tony Kråknes, Solfrid Håbrekke, Hui Jin
Sider: 94 (Illustrert)
Utgivelsesår: 2013
ISBN: 978-82-536-1333-8
The handbook presents an updated version of the PDS method. Among new features are: Calculations for multiple safety systems; Slightly updated model for common cause calculations; More thorough discussion of different demand mode situations; How to incorporate the effect from reduced proof test coverage (PTC) in the reliability calculations; Review and update of the calculation formulas and examples. The PDS method is in line with the main principles advocated in the standards IEC 61508 and IEC 61511 which have become important standards for specification, design and operation of safety instrumented systems in the process industry.
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1 Introduction
- Purpose of the Handbook
- Organisation of the Handbook
- Abbreviations
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2 The Need for Reliability Calculations
- Why do we need Reliability Analysis of Safety Instrumented Systems
- Why PDS?
- Uncertainty in Reliabililty Analysis
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3 Reliability Concepts
- Introduction
- Failure Classification by Cause of Failure
- How to make the Reliability Calculations more realistic
- Testing and Failure Detection
- Failure Mode Classification and Taxonomy
- Dangerous undetected Failures
- Performance Measures for Loss of Safety - Low Demand Systems
- Loss of Production
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4 Modelling of Common Cause Failures
- The PDS Extension of the Beta-Factor Model - Cmoon
- Proposed Values for Cmoon Factors
- Standard ß-factor Model versus PDS Approach
- Modelling of CCF for Components with Non-identical Characteristics
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5 PDS Calculation formulas - Low Demand Systems
- Assumptions and Limitations
- PDS Formulas for Loss of Safety
- How to Model the Quantitative Effect of Imperfect Functional Testing
- Quantification of Spurious Trip Rate (SPR)
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6 PDS Calculation Formulas - High Demand Systems
- High and Low Demand Systems
- Loss-of-safety Measures: PFD and PFH examples
- Using PFD or PFH?
- PHF Formulas; including both Common Cause and Independent Failures
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7 Calculations for Multiple Systems
- Background
- Motivation for using Correction Factors (CF) in Multiple SIS Calculations
- Correction Factors for Simultaneous Testing
- Correction Factors for Non-Simultaneous Testing
- Concluding Remarks
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8 Quantification Example
- System Description - Topside HIPPS Function
- Reliability Input Data
- Loss of Safety Assessment - CSU
- Spurious Trip Assessment
- 9 References
- Appendix A: Notations and Abbreviations
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Appendix B: The Configuration Factor Cmoon
- B.1 Determining the Configuration Factor Cmoon
- B.2 Formulas for the Configuration Factor Cmoon
- Appendix C: Detailed Formulas for PFD and DTU
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Appendix D: Multiple SIS - Background and Calculations
- D.1 Approaches to determining CF in case of simultaneous testing
- D.2 The effect of differences in testing
- Appendix E: PFD versus PFH and the effect of demands