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-109
Table 2.B.13.2—pH Temperature Function
Temperature
(°F)
pH
3.5 4.0 4.5 5.0 5.5 6.0 6.5
68 6.00 5.45 4.9 3.72 2.55 1.55 0.72
86 8.52 7.77 7.02 5.16 3.40 2.00 0.91
104 10.98 10.06 9.13 6.49 4.08 2.30 1.02
122 11.92 10.96 10.01 6.86 4.10 2.20 0.94
140 12.83 11.86 10.89 7.18 4.05 2.03 0.84
158 13.42 12.01 10.6 6.58 3.61 1.86 0.87
176 13.93 12.12 10.31 6.01 3.20 1.70 0.90
194 9.37 7.91 6.45 2.44 0.82 0.49 0.32
212 9.23 8.04 6.38 2.19 0.94 0.62 0.42
230 8.96 8.09 6.22 1.87 1.07 0.77 0.53
248 8.55 8.06 5.98 1.48 1.20 0.92 0.65
266 7.38 6.39 3.98 0.96 0.80 0.63 0.47
284 6.26 4.91 2.31 0.53 0.46 0.39 0.32
302 5.20 3.62 0.98 0.19 0.19 0.19 0.19
Table 2.B.13.2M—pH Temperature Function
Temperature
(°C)
pH
3.5 4.0 4.5 5.0 5.5 6.0 6.5
20 6.00 5.45 4.9 3.72 2.55 1.55 0.72
30 8.52 7.77 7.02 5.16 3.40 2.00 0.91
40 10.98 10.06 9.13 6.49 4.08 2.30 1.02
50 11.92 10.96 10.01 6.86 4.10 2.20 0.94
60 12.83 11.86 10.89 7.18 4.05 2.03 0.84
70 13.42 12.01 10.6 6.58 3.61 1.86 0.87
80 13.93 12.12 10.31 6.01 3.20 1.70 0.90
90 9.37 7.91 6.45 2.44 0.82 0.49 0.32
100 9.23 8.04 6.38 2.19 0.94 0.62 0.42
110 8.96 8.09 6.22 1.87 1.07 0.77 0.53
120 8.55 8.06 5.98 1.48 1.20 0.92 0.65
130 7.38 6.39 3.98 0.96 0.80 0.63 0.47
140 6.26 4.91 2.31 0.53 0.46 0.39 0.32
150 5.20 3.62 0.98 0.19 0.19 0.19 0.19