API RP 581 - 3rd Ed.2016 - Add.2-2020 - Risk-Based Inspection Methodology

2.B-102 API RECOMMENDED PRACTICE 581
2.B.12.8
Figures
Start
Determine Base Corrosion Rate
using Table 2.B.12.2.
Calculate Soil Resistivity
Factor using Table 2.B.12.3.
No
Soil Resistivity
considered for Base
CR ?
Yes
Determine Operating Temperature
factor using Table 2.B.12.4.
Determine Cathodic Protection System
effectiveness using Table 2.B.12.5.
Is there a coating?
No
Yes
Set Coating Effectiveness Factor
to 1.0
Determine Coating Effectiveness Factor
Using Table 2.B.12.6.
Calculate estimated
corrosion rate
Using Equation 2.B.21.
Estimated
Corrosion Rate
Figure 2.B.12.1—Soil-side Corrosion—Determination of Corrosion Rate