API Updated API-580 Exam Questions and Answers by carson

As defined in API 580, Section 3.1.59:

“Risk evaluation: The process used to compare the estimated risk against given risk criteria to determine the significance of the risk.”

This follows from the broader risk assessment process where risk identification and analysis occur first, followed by risk evaluation.

According to Section 7.2.3:

“Quantitative RBI uses logic models depicting combinations of events that could result in severe accidents and physical models depicting the progression of accidents… Hence more detailed information and data are needed for a fully quantitative RBI in order to provide input for the models.”

The need for detailed data in quantitative analysis is primarily to enable the use of logic and physical models in assessing risk.

As defined in Section 8.2 of API 580:

“Understanding equipment operation and the interaction with the process environment (both internal and external) and mechanical environment is key to identifying damage mechanisms… Examples include corrosion, cracking, erosion, and mechanical impacts.”

Further reinforced in the glossary and API RP 571, these are classified as damage mechanisms, which lead to specific damage modes and eventually failure modes.

Section 5.3.5 of API 580 explains the nature of semi-quantitative RBI analysis:

“Semi-quantitative… is geared to obtain the major benefits of the previous two approaches (e.g. speed of the qualitative and rigor of the quantitative)… The results are usually given in consequence and probabilitycategories or as risk numbers, but numerical values may be associated with each category to permit the calculation of risk and the application of appropriate risk acceptance criteria.”

Therefore, semi-quantitative assessments often produce risk values in a numeric format, allowing comparative decision-making. This distinguishes them from purely qualitative assessments that rely on subjective categories like “High/Medium/Low.”