API 510 Cheat Sheet 2026

The 30 highest-yield API 510 facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. What is the key safety concern in Radiographic Testing? → Radiation exposure
2. A newly certified API 510 inspector is unsure how to evaluate an unusual weld repair configuration. The best course of action is to: → Seek guidance from a more experienced inspector or engineer before proceeding
3. Which scenario represents a violation of the Certified Pressure Vessel Inspector code of professional conduct? → Misrepresenting qualifications or certification status
4. When a repair is made by welding on a vessel in hydrogen service, which additional concern must be addressed? → Hydrogen embrittlement risk and the need for bake-out procedures before welding
5. An API 510 inspector finds porosity clustered at the weld stop/start location. The most likely root cause is: → Contamination or improper arc restart technique
6. In Certified Pressure Vessel Inspector practice, what is the FIRST step when a safety hazard is identified in the workplace? → Immediately secure the area and report the hazard
7. Which professional attribute is most valued in welding inspection within the API 510 field? → Accountability and commitment to standards
8. What is the primary reason pneumatic testing is considered more hazardous than hydrostatic testing? → Compressed gas stores significantly more energy than liquid at the same pressure
9. API 510 defines the 'corrosion allowance' as the material provided beyond the minimum required thickness to account for: → Metal loss due to corrosion and erosion over the service life
10. According to API 510, what action is required when the actual material of a vessel component cannot be positively identified? → Test the material using PMI or other methods, or assume the lowest-grade material
11. Which document serves as the primary record for tracking all inspection activities and findings on a pressure vessel? → The equipment inspection history file
12. An inspector certified under API 510 is asked to inspect a vessel type outside their area of competence. The ethical response is to: → Decline and refer the work to a qualified specialist
13. Who must authorize repairs on a pressure vessel? → An authorized inspector
14. When conducting a risk assessment for API 510 operations, which factor should receive the HIGHEST priority? → Probability and severity of potential harm
15. Who is responsible for witnessing or reviewing the pressure test documentation for a vessel repair under API 510? → The authorized pressure vessel inspector (API 510)
16. What is 'amine stress corrosion cracking' and which vessel service is most at risk? → Cracking in carbon steel vessels handling amine solutions used in gas treating
17. A hydrogen-induced cracking (HIC) inspection of a carbon steel vessel operating in wet H₂S service should prioritize which NDT technique? → Straight beam UT or phased array UT to detect internal laminar cracking
18. Which scenario represents a violation of the Certified Pressure Vessel Inspector code of professional conduct? → Misrepresenting qualifications or certification status
19. Which professional attribute is most valued in documentation within the API 510 field? → Accountability and commitment to standards
20. Which professional attribute is most valued in repair and alteration within the API 510 field? → Accountability and commitment to standards
21. API 510 requires that inspection records include which minimum piece of information for each thickness measurement location? → The location of the measurement, thickness reading, and date
22. A carbon steel vessel operating in a caustic (NaOH) service exhibits cracking along welds. Which corrosion mechanism is MOST likely responsible? → Caustic stress corrosion cracking (caustic embrittlement)
23. When performing a weld overlay repair on a corroded vessel shell, the minimum thickness after repair must meet: → The required minimum thickness per applicable code
24. In the API 580/581 Risk-Based Inspection framework, risk is defined as the product of two factors. Which combination correctly defines risk? → Probability of failure (PoF) × consequence of failure (CoF)
25. Under API 510, the term 'fitness-for-service' (FFS) assessment is used to: → Evaluate whether a vessel with a flaw or damage can continue in service safely
26. A repair organization proposes to use a weld procedure not qualified to the current code edition for a vessel repair. Under API 510, this is: → Unacceptable; all WPS must be qualified per an applicable welding code
27. In ASME VIII Division 1, the 'U' stamp on a pressure vessel certifies that: → The vessel was fabricated in accordance with ASME Section VIII Division 1 requirements
28. A vessel exhibits uniform metal loss of 0.012 inches over a 2-year inspection interval. What is the calculated corrosion rate? → 0.006 in/yr
29. In API 510, 'localized corrosion' detected during inspection is typically evaluated using: → Point thickness measurements in the corroded area compared to t_minimum
30. A repair organization completing work on a pressure vessel in the field must have which of the following? → An R-stamp from the National Board of Boiler and Pressure Vessel Inspectors