API 570 Open Book vs Closed Book: What to Memorize
The API 570 exam is half closed book and half open book, but the split is by question count, not by effort. You get 110 closed-book questions in 2.75 hours, then 60 open-book questions in 3.75 hours. That is 1.5 minutes per closed-book question and 3.75 minutes per open-book question, on average. So memorize the methods and the vocabulary, and practice finding everything else fast. This article draws that line, using the API 570 certification page and Body of Knowledge. The next window is 29 January to 19 February 2027, with an application deadline of 26 November 2026 on API's schedule page (read 23 October 2026). Confirm it there before you pay.
What the two parts actually are
The exam day is 7.5 hours: a short tutorial, the closed-book part, a 45-minute lunch and the open-book part. Of 170 questions, 140 are scored and 30 are pretest questions you can't pick out, so treat every item as live.
API's Body of Knowledge describes the closed-book part as testing knowledge and tasks that call for everyday working knowledge of API 570 and its references. It describes the open-book part as using more detailed information that an inspector is expected to find in the documents but would not normally commit to memory. That one sentence is your study plan.
Papers, notes and books are not allowed in the testing center. During the open-book part, PDFs of the referenced publications appear on screen. API words which sections appear differently by program, so read the effectivity sheet guide and API's tutorial before exam day.
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Start the free 10-question checkWhat to memorize for the closed-book part
At 1.5 minutes a question there is no time to open a mental index. Aim to own these cold:
- Corrosion rate and remaining life. The Body of Knowledge says the formulas for corrosion rate, remaining life and the interval rules may be closed-book. Know the long-term and short-term versions and when each applies.
- Definitions and roles. Inspector, owner/user, repair, alteration, rerating, condition monitoring location and similar terms.
- Damage mechanism vocabulary. For the RP 571 paragraphs on the list, be able to name the mechanism, the material at risk and where it shows up in piping.
- Inspection types and purposes. What each type of inspection is for, and what each NDE method finds.
- Welding basics. Essential versus non-essential variables, and the logic of a procedure qualification.
A practical test: if you would need more than 90 seconds to find it in a book, it belongs in the memorize pile. Write each item as a one-line prompt and drill it in short sessions. The closed-book exam guide has a drill built on the same format, written for vessels.
What to look up in the open-book part
The open-book part rewards detail you would not carry in your head: a table value, a limit, a paragraph that lists what a record must hold. Typical lookup work for piping includes flange ratings, thermal expansion between two temperatures, weld joint quality factors, impact exemption temperatures and test pressure factors. The Body of Knowledge names the sections for each.
Your skill here is routing. Ask three things in order:
- Which publication holds this rule? (API 570, RP 574, RP 577, B31.3, B16.5, PCC-2 and so on)
- Which section or table is it likely in?
- Is a unit or a corrosion allowance hidden in the stem?
Drill it on your own copies with search disabled. Our open-book strategy guide lays out the full routine, and the Body of Knowledge article tells you which publications to build your tabs around.
A time budget with invented numbers
Say you sit the open-book part with 60 questions and 225 minutes. Here is one way to spend it:
- 40 questions you can route in about 2 minutes: 80 minutes
- 15 questions that need a calculation plus a lookup, about 5 minutes each: 75 minutes
- 5 hard ones you flagged, about 8 minutes each: 40 minutes
That adds up to 195 minutes, leaving 30 minutes to revisit flags and check units. If the same exam has you spending 6 minutes on every item, 60 items would use 360 minutes, which is 135 more than you have. That is why lookup speed is a trained skill, not a feature of knowing the material. The numbers are invented and personal; build your own from a timed practice block.
How to practice each part
- Closed-book blocks: 55 questions in 82 minutes is half of the closed-book part at exam pace. Work with a four-function calculator and no notes.
- Open-book blocks: 20 prompts of the form "where is the rule for X?" in 75 minutes, with a log of publication, section and minutes taken.
- Mixed blocks: shuffle both types in the last weeks, so you can change gears on the day.
Our dated plan, API 570 study plan before 26 November, places these blocks week by week, and API 570 practice questions gives three worked items to start from.
Next step
Take the free 10-question check at /api-570#q1 and note which misses were memory and which were lookups. Then see the plans at /api-570/offer#plans, and ask the study buddy at /study-assistant for a plan built around your exam date.
FAQ
Is the API 570 exam open book?
Partly. The closed-book part has 110 questions and allows no notes or books. The open-book part has 60 questions, and you use the PDFs of the publications that appear on your screen.
Can I bring my own copies of the codes?
No. API's page says papers, notes and books are not allowed in Prometric's centers. Your own copies are for studying, not for exam day.
How long is each part of the API 570 exam?
The closed-book part is 2.75 hours and the open-book part is 3.75 hours, with a 45-minute lunch between them. The whole day is 7.5 hours including a short tutorial.
Which part is harder?
That depends on you. Candidates who calculate often tend to feel faster in the closed-book part, and candidates who read codes often tend to feel faster in the open-book part. Time a block of each and compare your own numbers.
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Your next step
- 01Free API 570 check10 questions, untimed, about 23 minutes. Answers explained as you go.Start free
- 02Free sample lessonCorrosion rates, remaining life and inspection intervals: a full lesson from the course.Read the sample
- 03API 570 course$199. Lessons, timed practice exams and a plan around your exam date.See the plans
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