API 510 Fitness-for-Service Assessment 2 — Questions and Answers
Question 1: In API 579-1/ASME FFS-1, what Level of assessment requires the most detailed analysis, including numerical stress analysis?
- Level 1
- Level 2
- Level 3 (Correct answer)
- Level 4
Correct answer: Level 3
Level 3 assessments require the most rigorous analysis, often including finite element analysis or other advanced numerical methods.
Question 2: When performing an FFS assessment for a vessel with localized metal loss, what parameter defines the 'remaining strength factor' (RSF)?
- Ratio of failure pressure with flaw to failure pressure without flaw (Correct answer)
- Ratio of design pressure to allowable pressure
- Ratio of actual wall thickness to minimum required thickness
- Ratio of corrosion rate to inspection interval
Correct answer: Ratio of failure pressure with flaw to failure pressure without flaw
RSF is defined as the ratio of the predicted failure pressure of the component containing the flaw to the predicted failure pressure of the undamaged component.
Question 3: Under API 579, what is the minimum acceptable RSF value (RSFa) typically used in FFS assessments when the original design code is not known?
- 0.70
- 0.80 (Correct answer)
- 0.90
- 0.95
Correct answer: 0.80
API 579-1/ASME FFS-1 specifies a default RSFa of 0.90 but the most commonly referenced minimum acceptable RSF in practice for unknown codes defaults to 0.80 per the standard's allowable limit table.
Question 4: A vessel has a measured minimum thickness of 0.35 inches and a calculated minimum required thickness of 0.30 inches. What is the Remaining Life if the corrosion rate is 0.010 in/year?
- 2.5 years
- 5 years (Correct answer)
- 10 years
- 35 years
Correct answer: 5 years
Remaining life = (0.35 - 0.30) / 0.010 = 0.05 / 0.010 = 5 years.
Question 5: In FFS assessments for pressurized equipment, the term 'MAWP' refers to which of the following?
- Minimum Allowable Working Pressure
- Maximum Allowable Working Pressure (Correct answer)
- Mean Average Wall Pressure
- Maximum Assessed Weld Performance
Correct answer: Maximum Allowable Working Pressure
MAWP stands for Maximum Allowable Working Pressure, the highest permissible pressure at a specific temperature for continued operation.
Question 6: Which API 579 Part addresses the FFS assessment of pitting corrosion damage?
- Part 4
- Part 5 (Correct answer)
- Part 6
- Part 7
Correct answer: Part 5
API 579-1/ASME FFS-1 Part 5 specifically covers the assessment of local metal loss including pitting corrosion.
Question 7: During an FFS Level 1 assessment for general metal loss, what is the primary tool used to screen the damaged component?
- Finite element analysis model
- Thickness averaging and chart-based screening curves (Correct answer)
- Fracture toughness testing
- Hydrostatic pressure test at 1.5x MAWP
Correct answer: Thickness averaging and chart-based screening curves
Level 1 assessments use thickness averaging methods and tabulated or chart-based screening criteria that require minimal detailed calculations.
API 510 Fitness-for-Service Assessment 2
In API 579-1/ASME FFS-1, what Level of assessment requires the most detailed analysis, including numerical stress analysis?