API 510 Safety & Risk Management 3 — Questions and Answers
Question 1: In Risk-Based Inspection (RBI) methodology, the risk matrix combines probability of failure (POF) with which other factor?
- Consequence of failure (COF) (Correct answer)
- Cost of repair
- Inspector qualification level
- Equipment age
Correct answer: Consequence of failure (COF)
RBI risk is defined as the product of probability of failure (POF) and consequence of failure (COF), forming the basis of the risk matrix.
Question 2: Under API 510, when using RBI to set inspection intervals, the maximum allowable inspection interval for pressure vessels in highly corrosive service is governed by which standard?
- API 510 Section 6 (Correct answer)
- ASME Section VIII Div. 1
- API 580
- OSHA 29 CFR 1910.119
Correct answer: API 510 Section 6
API 510 Section 6 establishes the rules for inspection intervals, even when RBI methodologies per API 580/581 are used to justify extended intervals.
Question 3: A pressure vessel has a remaining corrosion allowance of 0.125 in. and a measured corrosion rate of 0.025 in./year. What is the estimated remaining life?
- 5 years (Correct answer)
- 3 years
- 10 years
- 2.5 years
Correct answer: 5 years
Remaining life = remaining corrosion allowance ÷ corrosion rate = 0.125 ÷ 0.025 = 5 years.
Question 4: In a Hazard and Operability (HAZOP) study, the term 'deviation' refers to:
- A departure from the design intent identified using guide words (Correct answer)
- A physical crack or defect in equipment
- An unauthorized change to process parameters
- A failure to follow inspection procedures
Correct answer: A departure from the design intent identified using guide words
In HAZOP, deviations are departures from design intent systematically identified by applying guide words (e.g., No, More, Less, Reverse) to process parameters.
Question 5: Which API standard provides the foundation for Risk-Based Inspection (RBI) methodology used in conjunction with API 510?
- API 580 and API 581 (Correct answer)
- API 570 and API 571
- API 653 and API 579
- API 510 and ASME PCC-2
Correct answer: API 580 and API 581
API 580 provides the RBI framework principles and API 581 provides the quantitative risk-based inspection methodology used alongside API 510.
Question 6: When consequence of failure (COF) in an RBI assessment includes a 'flammable fluid' scenario, inspectors must consider:
- Flash point, auto-ignition temperature, and inventory size (Correct answer)
- Only the operating pressure and temperature
- The vessel's original purchase cost
- The number of workers in the immediate area only
Correct answer: Flash point, auto-ignition temperature, and inventory size
Flammable COF calculations require flash point, auto-ignition temperature, and fluid inventory to estimate fire/explosion hazard magnitude.
Question 7: According to API 510, the 'next inspection date' for an internal inspection must not exceed half the remaining corrosion life or the maximum interval, whichever is:
- Shorter (Correct answer)
- Longer
- Equal to the design life
- Determined solely by the owner/user
Correct answer: Shorter
API 510 requires the next inspection date to be the shorter of half the remaining life or the maximum allowable inspection interval, ensuring conservative scheduling.
API 510 Safety & Risk Management 3
In Risk-Based Inspection (RBI) methodology, the risk matrix combines probability of failure (POF) with which other factor?