API RP 581 - 3rd Ed.2016 - Add.2-2020 - Risk-Based Inspection Methodology
2-72 API RECOMMENDED PRACTICE 581b) STEP 2—Based on the susceptibility in STEP 1, determine the Severity Index, S VI , from Table 11.3.c) STEP 3—Determine the time in service, age, since the last Level A, B, or C inspection was performedwith no cracking detected or cracking was repaired. Cracking detected but not repaired should beevaluated and future inspection recommendations based upon FFS evaluation.d) STEP 4—Determine the number of inspections and the corresponding inspection effectiveness categoryusing Section 12.9.2 for past inspections performed during the in-service time. Combine the inspectionsto the highest effectiveness performed using Section 3.4.3.e) STEP 5—Determine the base DF for PASCC,PASCCD fB, using Table 6.3 based on the number ofinspections and the highest inspection effectiveness determined in STEP 4 and the Severity Index, S VI ,from STEP 2.f) STEP 6—Calculate the escalation in the DF based on the time in service since the last inspection usingthe age from STEP 3 and Equation (2.28). In this equation, it is assumed that the probability for crackingwill increase with time since the last inspection as a result of increased exposure to upset conditionsand other non-normal conditions.PASCC11 .( fB ( ) )PASCCD f = min D ⋅ max[ age ,1. 0] , 5000(2.28)11.7 Nomenclatureageis the component in-service time since the last cracking inspection or service start datePASCCD fis the DF for PASCC crackingPASCCD fBis the base value of the DF for PASCC crackingS VIis the Severity Index11.8 ReferencesSee References [10], [46], [47], [48], [49], [50], [51], [52], [53], [54], [55], [56], and [57] in Section 2.2.
RISK-BASED INSPECTION METHODOLOGY, PART 2—PROBABILITY OF FAILURE METHODOLOGY 2-7311.9 TablesTable 11.1—Data Required for Determination of the DF—PASCCRequired DataSusceptibility (Low, Medium, High)Thermal history (solution annealed,stabilized before welding, stabilized afterwelding)Maximum operating temperature, °C (°F)Presence of sulfides, moisture, andoxygen:During operation? (Yes or No)During shutdown? (Yes or No)Downtime protection used? (Yes or No)Age (years)Inspection effectiveness categoryNumber of inspectionsCommentsThe susceptibility is determined by expert advice or using the procedures inthis section.Determine the thermal history of the material. Consider especially whetherthermal stabilization heat treatment was performed after all welding.Determine the maximum operating temperature of the component. Considerany high temperature exposure such as during decoking.Determine whether these constituents are present in the component. Ifuncertain, consult with a process engineer. Consider whether hightemperaturecomponent in sulfidic service is opened to environment duringshutdown.Determine whether downtime protection for PASCC has been provided perNACE RP0170. This may include soda ash washing, nitrogen blanketing, ordehumidification.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 beenperformed.
- Page 67 and 68: RISK-BASED INSPECTION METHODOLOGY,
- Page 69 and 70: RISK-BASED INSPECTION METHODOLOGY,
- Page 71 and 72: RISK-BASED INSPECTION METHODOLOGY,
- Page 73 and 74: RISK-BASED INSPECTION METHODOLOGY,
- Page 75 and 76: RISK-BASED INSPECTION METHODOLOGY,
- Page 77 and 78: RISK-BASED INSPECTION METHODOLOGY,
- Page 79 and 80: RISK-BASED INSPECTION METHODOLOGY,
- Page 81 and 82: RISK-BASED INSPECTION METHODOLOGY,
- Page 83 and 84: RISK-BASED INSPECTION METHODOLOGY,
- Page 85 and 86: RISK-BASED INSPECTION METHODOLOGY,
- Page 87 and 88: RISK-BASED INSPECTION METHODOLOGY,
- Page 89 and 90: RISK-BASED INSPECTION METHODOLOGY,
- Page 91 and 92: RISK-BASED INSPECTION METHODOLOGY,
- Page 93 and 94: RISK-BASED INSPECTION METHODOLOGY,
- Page 95 and 96: RISK-BASED INSPECTION METHODOLOGY,
- Page 97 and 98: RISK-BASED INSPECTION METHODOLOGY,
- Page 99 and 100: RISK-BASED INSPECTION METHODOLOGY,
- Page 101 and 102: RISK-BASED INSPECTION METHODOLOGY,
- Page 103 and 104: RISK-BASED INSPECTION METHODOLOGY,
- Page 105 and 106: RISK-BASED INSPECTION METHODOLOGY,
- Page 107 and 108: RISK-BASED INSPECTION METHODOLOGY,
- Page 109 and 110: RISK-BASED INSPECTION METHODOLOGY,
- Page 111 and 112: RISK-BASED INSPECTION METHODOLOGY,
- Page 113 and 114: RISK-BASED INSPECTION METHODOLOGY,
- Page 115 and 116: RISK-BASED INSPECTION METHODOLOGY,
- Page 117: RISK-BASED INSPECTION METHODOLOGY,
- Page 121 and 122: RISK-BASED INSPECTION METHODOLOGY,
- Page 123 and 124: RISK-BASED INSPECTION METHODOLOGY,
- Page 125 and 126: RISK-BASED INSPECTION METHODOLOGY,
- Page 127 and 128: RISK-BASED INSPECTION METHODOLOGY,
- Page 129 and 130: RISK-BASED INSPECTION METHODOLOGY,
- Page 131 and 132: RISK-BASED INSPECTION METHODOLOGY,
- Page 133 and 134: RISK-BASED INSPECTION METHODOLOGY,
- Page 135 and 136: RISK-BASED INSPECTION METHODOLOGY,
- Page 137 and 138: RISK-BASED INSPECTION METHODOLOGY,
- Page 139 and 140: RISK-BASED INSPECTION METHODOLOGY,
- Page 141 and 142: RISK-BASED INSPECTION METHODOLOGY,
- Page 143 and 144: RISK-BASED INSPECTION METHODOLOGY,
- Page 145 and 146: RISK-BASED INSPECTION METHODOLOGY,
- Page 147 and 148: RISK-BASED INSPECTION METHODOLOGY,
- Page 149 and 150: RISK-BASED INSPECTION METHODOLOGY,
- Page 151 and 152: RISK-BASED INSPECTION METHODOLOGY,
- Page 153 and 154: RISK-BASED INSPECTION METHODOLOGY,
- Page 155 and 156: RISK-BASED INSPECTION METHODOLOGY,
- Page 157 and 158: RISK-BASED INSPECTION METHODOLOGY,
- Page 159 and 160: RISK-BASED INSPECTION METHODOLOGY,
- Page 161 and 162: RISK-BASED INSPECTION METHODOLOGY,
- Page 163 and 164: RISK-BASED INSPECTION METHODOLOGY,
- Page 165 and 166: RISK-BASED INSPECTION METHODOLOGY,
- Page 167 and 168: RISK-BASED INSPECTION METHODOLOGY,
RISK-BASED INSPECTION METHODOLOGY, PART 2—PROBABILITY OF FAILURE METHODOLOGY 2-73
11.9 Tables
Table 11.1—Data Required for Determination of the DF—PASCC
Required Data
Susceptibility (Low, Medium, High)
Thermal history (solution annealed,
stabilized before welding, stabilized after
welding)
Maximum operating temperature, °C (°F)
Presence of sulfides, moisture, and
oxygen:
During operation? (Yes or No)
During shutdown? (Yes or No)
Downtime protection used? (Yes or No)
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 thermal history of the material. Consider especially whether
thermal stabilization heat treatment was performed after all welding.
Determine the maximum operating temperature of the component. Consider
any high temperature exposure such as during decoking.
Determine whether these constituents are present in the component. If
uncertain, consult with a process engineer. Consider whether hightemperature
component in sulfidic service is opened to environment during
shutdown.
Determine whether downtime protection for PASCC has been provided per
NACE RP0170. This may include soda ash washing, nitrogen blanketing, or
dehumidification.
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.
Change language