API 510 Code Compliance & Safety Regulations 3 — Questions and Answers
Question 1: The National Board Inspection Code (NBIC) is primarily used in conjunction with API 510 for which purpose?
- Establishing original design margins
- Governing repairs and alterations to pressure-retaining items (Correct answer)
- Setting chemical exposure limits near pressure vessels
- Certifying welders for new construction only
Correct answer: Governing repairs and alterations to pressure-retaining items
The NBIC (ANSI/NB-23) provides rules for inspection, repair, and alteration of pressure-retaining items after they leave the original manufacturer.
Question 2: Under API 510, an 'alteration' to a pressure vessel differs from a 'repair' in that an alteration:
- Uses only ASME-certified welders
- Changes the vessel from its original design configuration (Correct answer)
- Restores a vessel to its original condition
- Is only performed during scheduled turnarounds
Correct answer: Changes the vessel from its original design configuration
An alteration changes the vessel's design intent, pressure rating, or configuration, whereas a repair restores a vessel to a suitable condition without changing design intent.
Question 3: According to API 510, what document must be prepared and retained after completing an alteration to a pressure vessel?
- A pressure test waiver
- An alteration report filed with the National Board (Correct answer)
- A welding procedure qualification record only
- An OSHA Form 300 entry
Correct answer: An alteration report filed with the National Board
Alterations require an alteration report (typically NB Form R-2 or equivalent) that must be filed with the National Board and retained by the owner.
Question 4: Which API standard specifically addresses Risk-Based Inspection (RBI) methodology for pressure vessels?
- API 570
- API 580 and API 581 (Correct answer)
- API 653
- API 571
Correct answer: API 580 and API 581
API 580 provides RBI principles and API 581 provides the detailed risk-based inspection technology methodology for pressure vessels and piping.
Question 5: In API 510, the term 'corrosion allowance' refers to:
- Extra material thickness added at fabrication to account for future corrosion (Correct answer)
- The maximum allowable corrosion rate before shutdown
- A factor applied to inspection frequency calculations
- The tolerance on wall thickness measurements
Correct answer: Extra material thickness added at fabrication to account for future corrosion
Corrosion allowance is additional thickness built into the vessel design at fabrication to account for anticipated metal loss during the vessel's service life.
Question 6: When performing a hydrostatic test per ASME Section VIII Division 1, the test pressure is typically:
- Equal to the MAWP
- 1.3 times the MAWP (adjusted for temperature)
- 1.5 times the MAWP (adjusted for temperature) (Correct answer)
- 2.0 times the MAWP at ambient temperature
Correct answer: 1.5 times the MAWP (adjusted for temperature)
ASME Section VIII Division 1 requires hydrostatic test pressure of 1.5 times MAWP, adjusted for the ratio of allowable stresses at test vs. design temperature.
Question 7: Under API 510, pressure vessels subject to internal corrosion shall have the remaining corrosion allowance measured to determine the:
- Last inspection date only
- Remaining life and next inspection interval (Correct answer)
- Weld quality rating
- Pressure relief valve set point
Correct answer: Remaining life and next inspection interval
Thickness measurements are used to calculate remaining life (remaining corrosion allowance ÷ corrosion rate), which then drives the next inspection interval.
API 510 Code Compliance & Safety Regulations 3
The National Board Inspection Code (NBIC) is primarily used in conjunction with API 510 for which purpose?