Potential source of errors in rbi analysis regarding data quality are the following except

The question asks to identify which option is NOT a source of error. Using the specified nominal thickness from design documents as the original thickness is an accepted industry practice when baseline inspection data is unavailable. While not as accurate as an actual measurement, it is a recognized and valid starting point for corrosion rate calculations in an RBI analysis. It is considered a standard assumption, not an error. In contrast, using current thickness readings (either averaged or maximum) to represent the original thickness is a significant methodological error.

B. Using averaged current thickness readings as the original thickness is a major error, as it ignores all metal loss that has already occurred.
C. Using the maximum current thickness reading as the original thickness is also an error, as it will lead to an underestimation of the true corrosion rate.

1. API Recommended Practice 580, Risk-Based Inspection, 3rd Edition, 2016, Section 7.3.2: "If baseline thickness measurements were not taken, the nominal thickness of the component may be used for the original thickness." This statement validates option A as an acceptable practice, not an error.