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

RISK-BASED INSPECTION METHODOLOGY, PART 2—PROBABILITY OF FAILURE METHODOLOGY 2-79
12.8 References
See References [10], [58], [59], [60], [61], [62], [63], and [64] in Part 1, Section 2.2.
12.9 Tables
Table 12.1—Data Required for Determination of the DF—ClSCC
Required Data
Susceptibility (Low, Medium, High)
Cl − concentration of process water (ppm)
Operating temperature, °C (°F)
pH of process water
Age (years)
Inspection effectiveness category
Number of inspections
Comments
The susceptibility is determined by expert advice or using the
procedures in this section.
Determine the bulk Cl − concentration of the water phase. If
unknown, the default value for ppm is >1000. Consider Cl −
content of any water present in system (i.e. hydrotest, boiler
feed, steam). Also, consider the possibility of concentration of
Cl − by evaporation or upset conditions.
Determine the highest operating temperature expected during
operation (consider normal and non-normal operating
conditions).
Determine pH of the process water. High pH solutions with
high chlorides generally are not as susceptible to cracking as
low pH solution with chlorides.
Use inspection history to determine the time since the last SCC
inspection.
The effectiveness category that has been performed on the
component.
The number of inspections in each effectiveness category that
have been performed.