API 510 Code Compliance & Safety Regulations 5 — Questions and Answers
Question 1: API 510 allows the on-stream inspection interval for external inspections to be extended up to a maximum of:
- 3 years
- 5 years (Correct answer)
- 10 years
- 15 years
Correct answer: 5 years
API 510 permits external on-stream inspection intervals up to a maximum of 5 years unless RBI analysis justifies a different interval within allowed limits.
Question 2: Under API 510, what is the maximum internal or on-stream inspection interval for pressure vessels not subject to an RBI program?
- 5 years or half the remaining life, whichever is less
- 10 years or half the remaining life, whichever is less (Correct answer)
- 15 years regardless of remaining life
- 20 years for low-pressure vessels only
Correct answer: 10 years or half the remaining life, whichever is less
Without RBI, API 510 limits internal or equivalent on-stream inspection intervals to 10 years or half the calculated remaining corrosion life, whichever is less.
Question 3: A weld repair on a pressure vessel shell requires post-weld heat treatment (PWHT). Under API 510, who must authorize the PWHT procedure before work begins?
- The plant welding engineer alone
- The Authorized Inspector (Correct answer)
- The National Board regional office
- The state boiler inspector
Correct answer: The Authorized Inspector
The Authorized Inspector must review and authorize the repair procedure, including PWHT requirements, before repairs commence.
Question 4: Under ASME Section VIII Div. 1, the 'U' stamp on a nameplate signifies that:
- The vessel passed an ultrasonic examination
- The vessel was manufactured in compliance with ASME Section VIII Div. 1 (Correct answer)
- The vessel is rated for ultra-high-pressure service
- The vessel has an unlimited service life
Correct answer: The vessel was manufactured in compliance with ASME Section VIII Div. 1
The 'U' stamp is the ASME certification mark indicating the vessel was designed and fabricated in accordance with ASME Section VIII Division 1.
Question 5: Which API 510 concept allows continued operation of a vessel with a known flaw when a rigorous engineering analysis demonstrates the vessel remains safe?
- Derating to lower MAWP only
- Fitness-for-Service (FFS) assessment per API 579-1 (Correct answer)
- Grandfathering under the original construction code
- Hydrotest waiver form submission
Correct answer: Fitness-for-Service (FFS) assessment per API 579-1
API 579-1/ASME FFS-1 provides engineering methods to assess whether vessels with flaws, damage, or degradation are fit for continued service.
Question 6: Under API 510, when a pressure vessel has been out of service and is being returned to service, the inspector should:
- Accept the previous inspection record without further review
- Perform an inspection appropriate to the vessel's condition and service history (Correct answer)
- Require a full hydrostatic test in all cases
- Simply verify the PRV is operational
Correct answer: Perform an inspection appropriate to the vessel's condition and service history
Before returning an idle vessel to service, the inspector must evaluate its condition and service history to ensure it is safe and code-compliant for the intended service.
Question 7: The API 510 code applies to pressure vessels in what pressure range?
- Only vessels above 3000 psig
- Vessels with internal or external design pressure greater than 15 psig (Correct answer)
- All vessels regardless of pressure
- Only vessels between 150 and 3000 psig
Correct answer: Vessels with internal or external design pressure greater than 15 psig
API 510 generally covers pressure vessels designed and built to operate at internal or external pressures exceeding 15 psig, aligning with ASME Section VIII scope.
API 510 Code Compliance & Safety Regulations 5
API 510 allows the on-stream inspection interval for external inspections to be extended up to a maximum of: