API 580 Risk Based Inspection Practice Test

What does the ISO-risk line represent in a 2-3 plot regarding risk levels?

1. A line of constant risk with varying POF and COF values

2. Risk increases toward the lower left-hand corner

3. Components on the ISO risk line have different risk levels

4. A line showing identical risk levels for varying POF and COF

The correct answer is: A line showing identical risk levels for varying POF and COF

The ISO-risk line in a 2-3 plot represents a line showing identical risk levels for varying Probability of Failure (POF) and Consequence of Failure (COF). This line demonstrates how different combinations of POF and COF can yield the same overall risk. In a risk-based inspection context, understanding the ISO-risk line is essential for evaluating assets and determining where resources should be allocated for inspection and maintenance. By tracing along the ISO-risk line, one can see that as POF increases, COF must decrease to maintain the same risk level, and vice versa. This concept is crucial when making decisions about asset management, as it highlights how adjustments in either POF or COF can impact overall risk assessments. In contrast to this understanding, other options suggest misinterpretations of the ISO-risk line or its implications, leading to confusion on how risk levels are portrayed in the 2-3 plot context.