Repair, Alteration & Rerating Procedures Flashcards
7 cards from real API 510 practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Repair, Alteration & Rerating Procedures flashcards as text
API 510 states that the inspector should review which documents before approving a repair involving welding?
Answer: Welding procedure specifications (WPS), welder qualifications, and the repair plan
Before approving welded repairs, the inspector must review and verify the WPS, welder performance qualifications, and the overall repair plan.
A steel pressure vessel shell has corroded to a thickness below the minimum required. The owner plans to restore it by welding a full encirclement sleeve. This is considered a:
Answer: Permanent repair if designed and executed to applicable code requirements
A properly designed and installed full encirclement sleeve welded per applicable code can be a permanent repair restoring pressure-containing integrity.
Under API 510, when does a change in service fluid (e.g., from water to a lethal gas) require the vessel to be treated as an alteration?
Answer: When the new service results in more severe conditions not covered by the original design or code requirements
A service change is an alteration when the new conditions (pressure, temperature, corrosivity, or lethal service classification) exceed the original design intent.
After completing an alteration, the 'R' stamp holder must update the nameplate to show:
Answer: The new MAWP, temperature, and the 'R' stamp number with the alteration year
Following an alteration, the nameplate must be updated to reflect the revised MAWP, temperature rating, and the R-stamp holder's mark with the year of alteration.
When calculating the MAWP for rerating a vessel shell, the inspector uses the 'actual measured thickness' rather than the nominal thickness because:
Answer: Nominal thickness always overstates the actual metal available after corrosion and mill tolerance
After service, corrosion and mill under-tolerance reduce wall thickness below nominal, so the actual measured value provides a more accurate and conservative MAWP.
API 510 requires that any hot-tap performed on an in-service pressure vessel be:
Answer: Evaluated and approved by the authorized inspector and supported by engineering analysis
Hot-tapping on in-service vessels requires engineering evaluation of risks and explicit approval by the authorized inspector before proceeding.
A vessel was originally built with a joint efficiency (E) of 0.70 (spot radiographed). If during rerating the inspector upgrades the joint efficiency to 1.0 by performing full radiography of all welds, the MAWP will:
Answer: Increase because the allowable stress is effectively higher at E=1.0
MAWP is directly proportional to joint efficiency (E); upgrading from E=0.70 to E=1.0 through full radiography increases the calculated MAWP by approximately 43%.