Risk Analysis

Terje Aven, University of Stavanger, Norway.

• Preface ix1 What is a risk analysis? 11.1 Why risk analysis? 31.2 Risk management 41.2.1 Decision-making under uncertainty 61.3 Examples: decision situations 111.3.1 Risk analysis for a tunnel 111.3.2 Risk analysis for an offshore installation 111.3.3 Risk analysis related to a cash depot 122 What is risk? 132.1 The risk concept and its description 132.2 Vulnerability 192.3 How to describe risk quantitatively 192.3.1 Description of risk in a financial context 212.3.2 Description of risk in a safety context 222.4 Qualitative judgements 243 The risk analysis process: planning 283.1 Problem definition 283.2 Selection of analysis method 333.2.1 Checklist-based approach 353.2.2 Risk-based approach 364 The risk analysis process: risk assessment 384.1 Identification of initiating events 384.2 Cause analysis 394.3 Consequence analysis 404.4 Probabilities and uncertainties 424.5 Risk picture: risk presentation 434.5.1 Handling the background knowledge 464.5.2 Risk evaluation 475 The risk analysis process: risk treatment 495.1 Comparisons of alternatives 495.1.1 How to assess measures? 515.2 Management review and judgement 536 Risk analysis methods 556.1 Coarse risk analysis 556.2 Job safety analysis 606.3 Failure modes and effects analysis 626.3.1 Strengths and weaknesses of an FMEA 686.4 Hazard and operability studies 696.5 SWIFT 706.6 Fault tree analysis 706.6.1 Qualitative analysis 736.6.2 Quantitative analysis 756.7 Event tree analysis 776.7.1 Barrier block diagrams 796.8 Bayesian networks 796.9 Monte Carlo simulation 827 Safety measures for a road tunnel 847.1 Planning 847.1.1 Problem definition 847.1.2 Selection of analysis method 857.2 Risk assessment 867.2.1 Identification of initiating events 867.2.2 Cause analysis 887.2.3 Consequence analysis 887.2.4 Risk picture 917.3 Risk treatment 937.3.1 Comparison of alternatives 937.3.2 Management review and decision 938 Risk analysis process for an offshore installation 958.1 Planning 958.1.1 Problem definition 958.1.2 Selection of analysis method 968.2 Risk analysis 968.2.1 Hazard identification 968.2.2 Cause analysis 968.2.3 Consequence analysis 998.3 Risk picture and comparison of alternatives 1018.4 Management review and judgement 1029 Production assurance 1039.1 Planning 1039.2 Risk analysis 1039.2.1 Identification of failures 1039.2.2 Cause analysis 1049.2.3 Consequence analysis 1049.3 Risk picture and comparison of alternatives 1069.4 Management review and judgement. Decision 10710 Risk analysis process for a cash depot 10810.1 Planning 10810.1.1 Problem definition 10810.1.2 Selection of analysis method 10910.2 Risk analysis 11010.2.1 Identification of hazards and threats 11010.2.2 Cause analysis 11010.2.3 Consequence analysis 11310.3 Risk picture 11510.4 Risk-reducing measures 11710.4.1 Relocation of the NOKAS facility 11810.4.2 Erection of a wall 11810.5 Management review and judgement. Decision 11910.6 Discussion 11911 Risk analysis process for municipalities 12111.1 Planning 12111.1.1 Problem definition 12111.1.2 Selection of analysis method 12211.2 Risk assessment 12211.2.1 Hazard and threat identification 12211.2.2 Cause and consequence analysis. Risk picture 12511.3 Risk treatment 12612 Risk analysis process for the entire enterprise 12812.1 Planning 12812.1.1 Problem definition 12812.1.2 Selection of analysis method 12912.2 Risk analysis 12912.2.1 Price risk 12912.2.2 Operational risk 13212.2.3 Health, environment and safety (HES) 13412.2.4 Reputation risk 13512.3 Overall risk picture 13712.4 Risk treatment 13813 Discussion 13913.1 Risk analysis as a decision support tool 13913.2 Risk is more than the calculated probabilities and expected values 14013.3 Risk analysis has both strengths and weaknesses 14113.3.1 Precision of a risk analysis: uncertainty and sensitivity analysis 14113.3.2 Terminology 14313.3.3 Risk acceptance criteria (tolerability limits) 14513.4 Reflection on approaches, methods and results 14813.5 Limitations of the causal chain approach 14813.6 Risk perspectives 15013.7 Scientific basis 15313.8 The implications of the limitations of risk assessment 15513.9 Critical systems and activities 15713.10 On the difference between risk as seen from the perspectives of the analysts and management 16213.11 Conclusions 165A Probability calculus and statistics 167A.1 The meaning of a probability 167A.2 Probability calculus 168A.3 Probability distributions: expected value 170A.3.1 Binomial distribution 171A.4 Statistics (Bayesian statistics) 172B Introduction to reliability analysis 174B.1 Reliability of systems composed of components 174B.2 Production system 176B.3 Safety system 176C Approach for selecting risk analysis methods 178C.1 Expected consequences 178C.2 Uncertainty factors 179C.3 Frame conditions 182C.4 Selection of a specific method 182D Terminology 184D.1 Risk management: Relationships between key terms 186Bibliography 188Index 195