API 510 Standards & Best Practices 4 — Questions and Answers
Question 1: According to API 510, what action is required when a pressure vessel inspection reveals that the calculated remaining life is less than four years?
- The vessel must be immediately taken out of service
- The next inspection shall be performed at half the remaining life or two years, whichever is less (Correct answer)
- A fitness-for-service assessment must be completed before the next turnaround
- The maximum allowable working pressure must be derated by 25%
Correct answer: The next inspection shall be performed at half the remaining life or two years, whichever is less
When remaining life is less than four years, API 510 requires the next inspection interval to be set at half the remaining life or two years, whichever is less.
Question 2: Which API standard is specifically referenced in API 510 for inspection, repair, alteration, and rerating of pressure vessels in refineries?
- API 570
- API 653
- API 510 itself (Correct answer)
- API 936
Correct answer: API 510 itself
API 510 is itself the standard covering inspection, repair, alteration, and rerating of in-service pressure vessels used in the petroleum and chemical process industries.
Question 3: According to API 510, what minimum documentation must be kept for each pressure vessel in a facility?
- Original purchase invoices and shipping records
- Vessel identification, design data, inspection history, and repair/alteration records (Correct answer)
- Operator training certificates and safety drill logs
- Insurance appraisals and replacement cost estimates
Correct answer: Vessel identification, design data, inspection history, and repair/alteration records
API 510 requires maintaining records that include vessel identification, design data, inspection results, and records of any repairs or alterations.
Question 4: In API 510 terminology, what distinguishes a 'repair' from an 'alteration'?
- A repair restores original design conditions; an alteration changes design temperature, pressure, or configuration (Correct answer)
- A repair requires ASME Code stamping; an alteration does not
- A repair is performed during operation; an alteration requires shutdown
- A repair is documented internally; an alteration requires jurisdictional approval
Correct answer: A repair restores original design conditions; an alteration changes design temperature, pressure, or configuration
Under API 510, a repair returns a vessel to its original design condition, while an alteration changes design temperature, pressure, capacity, or structural configuration.
Question 5: When an in-service pressure vessel is rerated to a higher MAWP under API 510, which of the following is required?
- Only a visual inspection by a certified operator
- Review by an engineer experienced in pressure vessel design and approval by the authorized inspector (Correct answer)
- A full hydrostatic test at 1.5 times the new MAWP
- Replacement of all pressure boundary welds
Correct answer: Review by an engineer experienced in pressure vessel design and approval by the authorized inspector
Rerating to a higher MAWP requires engineering review by a qualified engineer and approval by the authorized inspector, along with appropriate inspection and testing.
Question 6: According to API 510, what is the maximum internal inspection interval for pressure vessels in most services?
- 5 years
- 10 years (Correct answer)
- 15 years
- 20 years
Correct answer: 10 years
API 510 sets the maximum internal inspection interval at 10 years for most pressure vessels unless justified by RBI or other approved methods.
Question 7: Under API 510, which type of NDE method is considered most effective for detecting subsurface volumetric defects in vessel shell welds?
- Magnetic particle testing (MT)
- Liquid penetrant testing (PT)
- Radiographic testing (RT) or ultrasonic testing (UT) (Correct answer)
- Visual testing (VT)
Correct answer: Radiographic testing (RT) or ultrasonic testing (UT)
RT and UT are volumetric NDE methods capable of detecting internal or subsurface defects in welds, making them the most effective for that purpose.
API 510 Standards & Best Practices 4
According to API 510, what action is required when a pressure vessel inspection reveals that the calculated remaining life is less than four years?