Reliability Study Overview

The reliability analysis of a system cannot be undertaken without a precise definition of the system itself and of the actual goal (safety or production) of the study. When this is done, it is of utmost importance to understand how the system worksFunctional analysis (functional analysis) before trying to find out how it can failDysfunctional analysis (dysfunctional analysis). This chapter explains how to do that for qualitative, semi-quantitative or purely quantitative analyses by using the various available approaches. They are briefly described and compared. They range from simple approaches, used to identify the main issues (preliminary hazard analysis, PHA, hazard and operability study, HAZOP, failure modes, effects and criticality analysis, FMECAFailure modes, effects and criticality analysis (FMECA)), to more sophisticated approaches allowing more detailed analyses and quantitative probabilistic calculations (fault trees, reliability block diagrams, Markov graphs, Petri nets and Monte Carlo simulation). This chapter provides an introduction to the sophisticated approaches covered in detail in the other parts of the book but the simple approaches are not detailed anymore. The need for collecting and using accurate reliability data is brought to light for accurate probabilistic calculations and a few words are provided about comparison and decision process and prevention and risk mitigation means.