API 510 Repair and Alteration Standards 4 — Questions and Answers
Question 1: Under API 510, who is responsible for determining whether an alteration requires engineering review and design calculations?
- The authorized pressure vessel inspector in consultation with the owner/user (Correct answer)
- The repair organization's welder
- The local fire department
- Only an ASME-accredited manufacturer
Correct answer: The authorized pressure vessel inspector in consultation with the owner/user
The authorized pressure vessel inspector, working with the owner/user, determines whether a change qualifies as an alteration requiring engineering review.
Question 2: A vessel operating at a MAWP of 250 psi requires a pneumatic leak test after a repair. The typical pneumatic test pressure is:
- 1.1 times the MAWP (275 psi) (Correct answer)
- 1.5 times the MAWP (375 psi)
- Equal to the MAWP (250 psi)
- 2.0 times the MAWP (500 psi)
Correct answer: 1.1 times the MAWP (275 psi)
API 510 references ASME Section VIII, which specifies a pneumatic test pressure of 1.1 times the MAWP for pneumatic tests.
Question 3: When a shell plate section is replaced on a vessel constructed to ASME Section VIII Div. 1, the replacement material must have:
- An ASME material specification (SA or SB designation) with traceable material certification (Correct answer)
- Any equivalent commercial grade material
- A higher yield strength than the original plate
- The lowest available carbon content regardless of specifications
Correct answer: An ASME material specification (SA or SB designation) with traceable material certification
Replacement materials must conform to an ASME-listed specification with material test reports (MTRs) for full traceability.
Question 4: The primary purpose of magnetic particle testing (MT) after weld repair on a carbon steel vessel is to detect:
- Surface and near-surface cracks, laps, and seams open to or near the surface (Correct answer)
- Subsurface volumetric flaws deep in the base metal
- Corrosion rate of the parent metal
- Weld hardness and tensile strength
Correct answer: Surface and near-surface cracks, laps, and seams open to or near the surface
MT detects surface-breaking and near-surface discontinuities in ferromagnetic materials by revealing flux leakage at defect locations.
Question 5: When repairing a vessel with a stainless steel overlay cladding, the repair weld must be made with filler metal that:
- Matches or is compatible with the cladding alloy composition (Correct answer)
- Uses the base metal composition only
- Is always austenitic 308L regardless of cladding type
- Does not need to match because cladding is not a structural element
Correct answer: Matches or is compatible with the cladding alloy composition
Cladding repair filler metal must be compatible with the alloy being repaired to maintain corrosion resistance and prevent galvanic incompatibility.
Question 6: API 510 requires that repair and alteration records be maintained for:
- The life of the vessel (Correct answer)
- Five years only
- Until the next scheduled inspection
- As required by the manufacturer, with no specified minimum period
Correct answer: The life of the vessel
API 510 requires that all repair and alteration records be retained for the life of the pressure vessel.
Question 7: A corroded area found during inspection shows metal loss below the minimum required thickness (t_min). The most engineering-sound repair approach is to:
- Weld build-up or insert plate to restore thickness to at least t_min (Correct answer)
- Derate the MAWP without restoring metal
- Apply an internal epoxy coating and continue operating
- Monitor with UT every 30 days indefinitely without repair
Correct answer: Weld build-up or insert plate to restore thickness to at least t_min
Restoring the wall thickness to at least t_min via weld build-up or insert plate is the preferred repair; derating alone does not restore structural integrity.
API 510 Repair and Alteration Standards 4
Under API 510, who is responsible for determining whether an alteration requires engineering review and design calculations?