API 510 vs API 570: which API exam is right for you?
Both exams have the same format: 170 questions (140 scored), 110 closed book and 60 open book, over a 7.5-hour day at a Prometric test center. API 510 is for pressure vessels and centers on ASME Section VIII Division 1 calculations (shell and head thickness, MAWP, UG-99 test pressures). API 570 is for piping and replaces those with ASME B31.3 thickness and test pressures, B16.5 flange ratings, piping classes and circuit types. Welding (Section IX, RP 577), NDE (Section V) and several RP 571 mechanisms overlap, so a second certification takes less study than the first. Pick the one that matches the equipment you inspect.
API 510 vs API 570 at a glance
| API 510 | API 570 | |
|---|---|---|
| Full name | API 510 Pressure Vessel Inspector Exam | API 570 Piping Inspector Exam |
| Questions | 170 multiple-choice questions (140 scored, 30 unscored pretest items): 110 closed-book and 60 open-book | 170 multiple-choice questions (140 scored, 30 unscored pretest items): 110 closed-book and 60 open-book |
| Time | 7.5-hour exam day: short tutorial, 2.75 hours closed book, 45-minute lunch, 3.75 hours open book | 7.5-hour exam day: short tutorial, 2.75 hours closed book, 45-minute lunch, 3.75 hours open book |
| Passing score | Passing scaled score is 400 on API's 200 to 500 scale. The number of correct answers needed isn't published and varies by form; practice to 75% or higher | Passing scaled score is 400 on API's 200 to 500 scale. The number of correct answers needed isn't published and varies by form; practice to 75% or higher |
| Format | Closed-book part, then an open-book part with the effectivity-sheet code sections as on-screen PDFs. No paper books or notes; on-screen calculator | Closed-book part, then an open-book part with the effectivity-sheet code sections as on-screen PDFs. No paper books or notes; on-screen calculator |
| Cost | US$875 API member / US$1,125 non-member (2026 fee table); US$890 / US$1,140 (2027 fee table). Reschedule US$350, late application US$200 | US$875 API member / US$1,125 non-member (2026 fee table); US$890 / US$1,140 (2027 fee table). Reschedule US$350, late application US$200 |
| Languages | English; Spanish and Chinese translations available on request | English; Spanish, Chinese and Korean translations available on request |
| Where | Prometric test centers, in person only (no remote option for API 510) | Prometric test centers, in person only (no remote option for API 570) |
| Level | API Inspector Certification | API Inspector Certification |
What each exam covers
API 510
- Corrosion Rates, Remaining Life and Intervals
- Vessel Calculations (ASME Section VIII, Division 1)
- Damage Mechanisms and Inspection Practices
- Repairs, Alterations and Rerating
- Welding (ASME Section IX and API 577)
- Nondestructive Examination (ASME Section V)
- Relief Devices and Material Verification
API 570
- Corrosion Rates, Remaining Life and Intervals
- Piping Calculations (ASME B31.3)
- Flange Ratings (ASME B16.5)
- Damage Mechanisms and Inspection Practices
- Repairs, Alterations and Rerating
- Welding (ASME Section IX, B31.3 and API 577)
- NDE and Pressure-Relieving Devices
Which should you take?
Both exams have the same format: 170 questions (140 scored), 110 closed book and 60 open book, over a 7.5-hour day at a Prometric test center. API 510 is for pressure vessels and centers on ASME Section VIII Division 1 calculations (shell and head thickness, MAWP, UG-99 test pressures). API 570 is for piping and replaces those with ASME B31.3 thickness and test pressures, B16.5 flange ratings, piping classes and circuit types. Welding (Section IX, RP 577), NDE (Section V) and several RP 571 mechanisms overlap, so a second certification takes less study than the first. Pick the one that matches the equipment you inspect.
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FAQ
What is the difference between API 510 and API 570?
Both exams have the same format: 170 questions (140 scored), 110 closed book and 60 open book, over a 7.5-hour day at a Prometric test center. API 510 is for pressure vessels and centers on ASME Section VIII Division 1 calculations (shell and head thickness, MAWP, UG-99 test pressures). API 570 is for piping and replaces those with ASME B31.3 thickness and test pressures, B16.5 flange ratings, piping classes and circuit types. Welding (Section IX, RP 577), NDE (Section V) and several RP 571 mechanisms overlap, so a second certification takes less study than the first. Pick the one that matches the equipment you inspect.
Which is harder, API 510 or API 570?
API 510: 170 multiple-choice questions (140 scored, 30 unscored pretest items): 110 closed-book and 60 open-book in 7.5-hour exam day: short tutorial, 2.75 hours closed book, 45-minute lunch, 3.75 hours open book. API 570: 170 multiple-choice questions (140 scored, 30 unscored pretest items): 110 closed-book and 60 open-book in 7.5-hour exam day: short tutorial, 2.75 hours closed book, 45-minute lunch, 3.75 hours open book. The longer exam covers more ground, but the harder one is the one further from your daily work. Take both free practice tests to see where you stand.
Can I hold both API 510 and API 570?
Yes. API 510, 570 and 653 are separate certifications, and many inspectors hold two or all three. Each needs its own application, experience and exam, and each is renewed on its own three-year cycle.
How do I prepare for API 510 and API 570?
Start with the free practice test for each, then study by topic. Premium is per exam ($147 a month each), so most people start with the exam they'll sit first and add the second when they're ready.
More comparisons
Exam details are summarized from API's published information as of November 2026. Confirm with API before you book. APIInspectorExam is not affiliated with the American Petroleum Institute (API), ASME or Prometric.