API 653 Repair and Alteration 5 — Questions and Answers
Question 1: API 653 requires that repair documentation be retained for at least how long?
- 5 years after the repair
- 10 years after the repair
- The life of the tank (Correct answer)
- Until the next scheduled inspection
Correct answer: The life of the tank
API 653 requires that all repair and alteration records be maintained for the remaining life of the tank to support future inspection and fitness-for-service evaluations.
Question 2: When repairing a tank shell using a lap patch, what type of weld is required around the full perimeter of the patch per API 653?
- Partial penetration groove weld
- Full penetration butt weld
- Continuous fillet weld (Correct answer)
- Intermittent fillet weld
Correct answer: Continuous fillet weld
API 653 requires a continuous fillet weld around the entire perimeter of a lap patch to prevent crevice corrosion and ensure structural continuity.
Question 3: A tank inspector finds that a previous shell repair used an incorrect filler metal. Under API 653, what action should be taken?
- Document the finding and increase inspection frequency
- Perform a fitness-for-service assessment to determine if the repair is acceptable (Correct answer)
- Immediately remove the repair and re-weld with correct material
- Accept the repair if it has been in service for more than 5 years without failure
Correct answer: Perform a fitness-for-service assessment to determine if the repair is acceptable
API 653 supports a fitness-for-service approach to evaluate whether a non-conforming repair provides adequate structural integrity for continued service.
Question 4: What is the minimum preheat temperature required per API 653 when welding on a carbon steel tank shell with a plate thickness greater than 1 inch?
- No preheat required for carbon steel
- 100°F (38°C)
- 200°F (93°C) (Correct answer)
- 300°F (149°C)
Correct answer: 200°F (93°C)
API 653 references ASME Section VIII / API 650 preheat requirements, which typically require 200°F (93°C) minimum preheat for carbon steel plates exceeding 1 inch thickness.
Question 5: Per API 653, when repairing a tank annular plate, what is the minimum length of a replacement annular plate insert?
- 12 inches (300 mm)
- 18 inches (450 mm)
- 24 inches (600 mm) (Correct answer)
- 36 inches (900 mm)
Correct answer: 24 inches (600 mm)
API 653 requires annular plate replacements to be at least 24 inches (600 mm) long to ensure adequate weld joint quality and structural continuity.
Question 6: When API 653 requires a hydrostatic test after a major repair or alteration, what is the standard test fill level?
- 50% of the maximum design fill height
- To the maximum design liquid level or the top of the shell, whichever is lower (Correct answer)
- To the overflow level only
- To the height of the repair location plus 3 feet
Correct answer: To the maximum design liquid level or the top of the shell, whichever is lower
API 653 requires hydrostatic testing to the maximum design liquid level or the top of the shell, whichever is lower, to verify the full repair under design conditions.
Question 7: According to API 653, which condition would classify a tank shell repair as requiring an authorized inspector to witness and sign off?
- Any cosmetic weld repair to the shell exterior
- Repairs involving replacement of shell plate material or structural welds (Correct answer)
- Painting or coating repairs to the shell surface
- Installation of tank gauging equipment
Correct answer: Repairs involving replacement of shell plate material or structural welds
API 653 requires authorized inspector involvement for structural repairs such as plate replacement or structural weld repairs due to their impact on tank integrity.
API 653 Repair and Alteration 5
API 653 requires that repair documentation be retained for at least how long?