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

RISK-BASED INSPECTION METHODOLOGY, PART 2, ANNEX 2.B—DETERMINATION OF CORROSION RATES 2.B-57
Table 2.B.6.2M—HF Corrosion—Estimated Corrosion Rates (mmpy) for Carbon Steel
Temp. Velocity HF-in-Water Concentration (%)
(°C) (m/s) 1 3 7 20 30 40 60 80 90 >90
21.1-37.78
54.44
71.11
87.78
<1.524 0.76 2.54 7.62 17.78 20.32 17.78 3.81 0.51 0.20 0.05
>1.524 1.52 5.08 15.24 25.37 25.37 25.37 7.62 1.02 0.38 0.10
<1.524 2.54 8.89 25.37 25.37 25.37 25.37 12.70 1.27 0.64 0.18
>1.524 5.08 17.78 25.37 25.37 25.37 25.37 25.37 2.54 1.27 0.38
<1.524 10.16 25.37 25.37 25.37 25.37 25.37 25.37 6.35 2.54 0.64
>1.524 20.32 25.37 25.37 25.37 25.37 25.37 25.37 12.70 5.08 1.27
<1.524 25.37 25.37 25.37 25.37 25.37 25.37 25.37 25.37 10.16 2.54
>1.524 25.37 25.37 25.37 25.37 25.37 25.37 25.37 25.37 20.32 5.08
Table 2.B.6.3—HF Corrosion—Estimated Corrosion Rates (mpy) for Alloy 400
Temp.
(°F)
Aerated?
HF-in-Water Concentration (%)
1 2 5 6 63 64 80 81
80
125
175
200
No 1 1 1 10 10 1 1 2
Yes 10 10 10 25 25 10 10 15
No 1 1 1 15 15 5 5 3
Yes 10 10 10 30 30 20 20 15
No 5 5 5 20 20 10 10 5
Yes 20 20 20 100 100 50 50 20
No 10 10 10 20 20 20 20 10
Yes 100 100 100 200 200 200 200 100
Table 2.B.6.3M—HF Corrosion—Estimated Corrosion Rates (mm/y) for Alloy 400
Temp
(°C)
Aerated?
HF-in-Water Concentration (%)
1 2 5 6 63 64 80 81
27
52
79
93
No 0.03 0.03 0.03 0.25 0.25 0.03 0.03 0.05
Yes 0.25 0.25 0.25 0.64 0.64 0.25 0.25 0.38
No 0.03 0.03 0.03 0.38 0.38 0.13 0.13 0.08
Yes 0.25 0.25 0.25 0.76 0.76 0.51 0.51 0.38
No 0.13 0.13 0.13 0.51 0.51 0.25 0.25 0.13
Yes 0.51 0.51 0.51 2.54 2.54 1.27 1.27 0.51
No 0.25 0.25 0.25 0.51 0.51 0.51 0.51 0.25
Yes 2.54 2.54 2.54 5.08 5.08 5.08 5.08 2.54