Five Fatal Flaws in API 581
Risk is a term with a multitude of meanings ranging from the subjective to the mathematically exact. The ISO 31000 / Guide 73 broad definition is ‘effect of uncertainty on objectives’ which may be both positive or negative. Quantifying risk, both in absolute or relative sense, relies on the relationship: “Risk is the product of the probability of an event times the consequence of the event”. Used in an absolute sense this relationship produces a figure in the same units as those of the consequence -often a monetary unit – in the period of time considered, e.g. a year. In a relative sense, the equation can be used to judge the change of risk level. For instance, the effect of activities that change the probability of an event, or of measures that change the consequence of an event. In risk management relative risk is an important guide.
Integrity Management beyond RBI
RBI is an integrity management method based on a quantified probability of failure. Failure is the top-event of the failure hazard. Is it feasible to make remotely quantitative predictions about the likelihood of top events? Is it not more effective and accurate to analyze and monitor the root causes of the hazard? This paper examines the basics of RBI and concludes it is a flawed method that cannot possibly deliver on its promises of increased efficiency and safety. As an alternative an outline is given of an integrity management system based on a comprehensive aggregate of corrosion management techniques.