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. Why is Magnetic Particle Testing limited to ferromagnetic materials? → Only ferromagnetic materials can retain magnetic fields
2. Which type of pressure relief valve is MOST sensitive to variable or high superimposed back pressure, which can raise its effective set pressure? → Conventional spring-loaded pressure relief valve
3. Why is personal protective equipment (PPE) essential during inspection? → To protect inspectors from potential hazards
4. What should be monitored during a pressure hold period? → Pressure gauge readings for any pressure drops indicating leaks
5. Which technique is most suitable for volumetric inspection? → Radiographic Testing
6. What role does process fluid toxicity play in an RBI consequence of failure analysis? → It elevates the safety/health consequence, increasing overall risk ranking
7. Why is thickness data trending important in pressure vessel management? → It reveals corrosion rate changes and enables remaining life prediction
8. What is required for a welded joint to be accepted under ASME? → It must be inspected and meet quality criteria
9. Which welding defect is characterized by the failure of fusion between the weld metal and base metal? → Lack of fusion
10. Which type of pressure relief device provides zero leakage before activation and is non-reclosing after operation? → Rupture disk
11. Which NDT method is most suitable for detecting surface cracks in non-porous materials? → Liquid Penetrant Testing
12. Which organization enforces safety regulations in industrial workplaces? → OSHA
13. What is the primary cause of pitting corrosion in pressure vessels? → Localized breakdown of protective film
14. What defines the minimum design metal temperature (MDMT)? → The minimum allowable operating temperature
15. Under API 510 RBI provisions, what is the maximum allowable inspection interval for a pressure vessel when an RBI assessment is implemented? → 10 years for external inspection and 10 years for internal/on-stream inspection
16. In pressure relief valve terminology, what is 'blowdown'? → The difference between set pressure and reseating pressure
17. Which condition can lead to hydrogen-induced cracking (HIC)? → Presence of hydrogen and stress
18. According to API 510 and ASME Section IX, who is responsible for qualifying welding procedures used in pressure vessel repair? → The owner/operator or their contractor
19. Which API standard specifically covers the sizing, selection, and installation of pressure-relieving devices in petroleum and petrochemical plants? → API 520
20. What must be obtained before making repairs to a pressure vessel under API 510? → Authorization from the inspector and a detailed repair plan
21. What is the typical cause of stress corrosion cracking (SCC)? → Tensile stress and corrosive environment
22. Which material defect can be detected by radiographic testing? → Slag inclusion
23. In API 581 quantitative RBI, consequence of failure is typically expressed in terms of which two categories? → Safety/health consequences and financial/environmental consequences
24. What is hydrogen-induced cracking and why is it a concern for pressure vessels? → Hydrogen atoms diffuse into steel, causing embrittlement and cracking under stress
25. What is the primary limitation of visual testing (VT)? → It can only detect surface-accessible defects
26. Under API 510, an authorized inspector must review and accept which document before repair welding begins on a pressure vessel? → The repair plan and applicable WPS/PQR
27. Which inspection method is considered the most basic form of testing? → Visual Inspection
28. What is the difference between general and localized corrosion? → General affects uniform areas while localized concentrates in specific spots
29. At what multiple of design pressure is a hydrostatic test typically conducted? → 1.3 to 1.5 times design pressure
30. When is radiographic testing (RT) preferred for pressure vessel weld examination? → When volumetric examination of welds is required to detect internal discontinuities