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

2-104 API RECOMMENDED PRACTICE 581
Table 15.2—Corrosion Rates for Calculation of the DF—External Corrosion
Operating
Temperature
(°F)
Corrosion Rate as a Function of Driver 1 (mpy)
Severe Moderate Mild Dry
10 0 0 0 0
18 3 1 0 0
43 10 5 3 1
90 10 5 3 1
160 10 5 2 1
225 2 1 0 0
250 0 0 0 0
NOTE 1 Driver is defined as the atmospheric condition causing the corrosion rate. See Part 2, Section 15.6.2
for explanation of drivers.
NOTE 2 Interpolation may be used for intermediate values of temperature.
Table 15.2M—Corrosion Rates for Calculation of the DF—External Corrosion
Operating
Temperature
(°C)
Corrosion Rate as a Function of Driver 1 (mm/y)
Severe Moderate Mild Dry
−12 0 0 0 0
−8 0.076 0.025 0 0
6 0.254 0.127 0.076 0.025
32 0.254 0.127 0.076 0.025
71 0.254 0.127 0.051 0.025
107 0.051 0.025 0 0
121 0 0 0 0
NOTE 1 Driver is defined as the atmospheric condition causing the corrosion rate. See Part 2, Section 15.6.2
for explanation of drivers.
NOTE 2 Interpolation may be used for intermediate values of temperature.