API 510 Practice Test: How to Take One That Counts

Match the real exam's shape

Per API's exam page and our closed-book guide:

• Closed-book part: 110 questions in 2.75 hours, which is 1.5 minutes per question.
• Open-book part: 60 questions in 3.75 hours, which is 3.75 minutes per question.
• Lunch break: 45 minutes between the parts.
• Scored questions: 140 of the 170. The other 30 are pretest, and you can't tell which.

A practice test that gives you one flat 170 questions with no split, or two minutes per question across the board, trains the wrong pacing. Split your practice the same way. Closed-book blocks get a calculator and scratch paper only. Open-book blocks get your own copies of the references on the effectivity sheet, with no search function, which is how the on-screen viewer behaves, as our open-book guide explains.

You don't need to sit all 170 at once every time. A useful rhythm is one full-length run about three weeks out, and shorter blocks before and after it.

Three original sample items

Invented numbers, original wording. Open your own copies for the sections named.

1. Short-term corrosion rate. The last two thickness readings at a vessel shell location are 0.448 in. and 0.430 in., taken 3 years apart. What is the short-term corrosion rate?

• A. 0.006 in. per year
• B. 0.018 in. per year
• C. 0.060 in. per year
• D. 0.143 in. per year

Answer: A. The loss between the two readings is 0.018 in., and 0.018 divided by 3 is 0.006 in. per year. B is the loss with no time. C divides the loss by 0.3. D divides the newer thickness by 3.

2. Static head. A liquid with specific gravity 1.0 fills a vertical vessel. A nozzle sits 35 ft below the point where MAWP is stated. Using 0.433 psi per foot, what static head acts at the nozzle?

• A. 8.1 psi
• B. 15.2 psi
• C. 35.0 psi
• D. 12.4 psi

Answer: B. 35 × 0.433 = 15.2 psi. A divides 35 by 4.33. C treats feet as psi. D uses 0.354, a wrong factor. Check it in the static head calculator.

3. Navigation. You need the rules for who authorizes a weld repair on a vessel in service. Which document do you open first?

• A. API 510, the section on repairs and alterations
• B. RP 576
• C. Section V
• D. RP 572

Answer: A. API 510 Section 8 covers repairs and alterations, including inspector authorization before the work starts. RP 576 covers pressure-relieving devices, Section V covers examination methods and RP 572 covers inspection practices. A closed-book habit gets you to the topic. The open-book habit gets you to the paragraph in under two minutes.

Practice the formats too

API's exam tutorial shows four question formats: multiple choice, multiple response, drag and drop, and extended matching. The last two get no partial credit, so one wrong placement fails the whole item. Put a few of each into your practice blocks so the screen holds no surprises on the day. Use a four-function calculator in closed-book blocks, since the exam's on-screen calculator is non-scientific.

Take the test in four passes

1. Sit the timed block. Don't pause the clock for a lookup. Flag items you'd come back to, as the real screen lets you.
2. Mark every miss by type. Concept gap, setup error, arithmetic slip or slow lookup. Each type needs a different fix.
3. Redo each missed calculation with new numbers the next day. If the new version goes wrong, you learned the answer, not the method.
4. Write the section number for every miss. If you can't, that item goes on your navigation list.

How to read the score

An overall percentage is the least useful number on the page. The Body of Knowledge has five sections, and a score by section tells you which one to study next. A result of 80 percent on thickness calculations and 45 percent on welding procedure review is a clear instruction.

No practice score predicts your exam result. Question sets differ, and API equates passing scores across exam forms rather than curving them, as its pretest policy explains. Use scores to compare your own attempts, not to judge your odds. If your weakest section improves across two or three attempts, you are moving in the right direction.

If you have a score and need a schedule, the API 510 study plan for 30, 60 and 90 days builds one, and how hard the API 510 exam is explains where candidates struggle. Choosing paid prep? See what to look for in an API 510 prep course.

Next step

Take the free 10-question check at /api-510 to see exactly which topics to fix, then ask the study buddy at /study-assistant for a plan built around your exam date.

FAQ

Is there a free API 510 practice test?

Yes. Ten original items across the Body of Knowledge are free at /api-510, with an explanation for each answer and no signup. API's own tutorial adds practice screens for the question formats, on general topics.

How many practice tests should I take?

Two or three full-length runs, spaced out, with the review between them, are enough for most candidates. The review matters more than the count.

Should I use my own code books in practice?

Yes, in open-book blocks. Use the editions on API's effectivity sheet for your window, since older editions can point to the wrong paragraph.

Do practice tests use real exam items?

Ours don't. Real or recalled items break the Code of Conduct you agree to when you apply, and API can cancel results or deny certification for it.