Risk Based Inspection – Metric

Risk based inspection Metric     Risk Based Inspection is a study to develop inspection plan based on equipment risk ranking. Mathematically, Risk is defined as PoF x CoF. What is PoF ? PoF or Probability of failure is a rank that tell us about how likely a equipment will fail. CoF or Consequence of failure is a rank that tell us about how much failure impacts. In a simple way PoF, CoF and Risk are 3 terms that we used to rank all equipment in a company. Risk based inspection metric may consist of 3×3 , 4×4, 5×5 or even 6×6. For a company has a small quantity of equipment, they may choose to use 3×3 metric. But for company that have a lot of equipment -e.g. 1,000,000- with wide range of consequence, they may prefer to use 6×6 metric. This metric tell us about how detail we group the equipment. In 6×6 metric, we group probability of failure to 6 categories and group consequence of failure to 6 categories. Risk based inspection approach Risk based inspection may use qualitative approach, quantitative approach or even semi-quantitative approach. In qualitative approach, we likely use “expert” team to qualify the PoF[…]

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