EXAM GUIDE · CHECKED 27 SEPTEMBER 2026
API 571 Exam Guide
API 571 Corrosion and Materials certification exam: format, eligibility, the single publication it is drawn from, and how to prepare for a closed-book paper on damage mechanisms. Every exam fact on this page comes from API's own documents, linked at the bottom. Where API has not published something, this page does not guess.
Exam format
| Questions | 110 in total: 100 scored and 10 unscored pretest questions |
|---|---|
| Format | Closed book throughout — there is no open-book part |
| Exam length | 3.25 hours |
| Delivery | Computer-based, either in person at a test centre or through remote proctoring |
| References | None. Paper and reference materials are not allowed into the exam |
| Body of Knowledge | The entire API RP 571, 3rd edition (2020) |
| Passing score | API states a set passing scaled score and does not publish the number. Anyone quoting one is guessing |
| Certification | Valid for three years, then recertification |
Time per question
The two parts are timed separately, and the time available per question is very different. Worked out from API's published timings:
CLOSED BOOK
1.8min per question
110 questions in 195 minutes
Eligibility
API sets a minimum amount of experience that depends on your education, and issues the certification only once your application has no open deficiencies.
| EDUCATION | EXPERIENCE | IN |
|---|---|---|
| A current API 510, 570 or 653 certification | None | Holding any one of the three qualifies you automatically |
| BS or higher in engineering or technology | 1 year | Any experience in the petrochemical industry, acquired within the last 10 years |
| 2-year degree or certificate in engineering or technology | 2 years | Any experience in the petrochemical industry, acquired within the last 10 years |
| High school diploma or equivalent | 3 years | Any experience in the petrochemical industry, acquired within the last 10 years |
| No formal education | 5 or more years | Any experience in the petrochemical industry, acquired within the last 10 years |
Publications examined
These are the editions on API's effectivity sheets. Where API limits the exam to certain sections, the list says so — anything outside those sections is not examined. The documents are copyrighted; buy them from an authorised seller.
For Current Body of Knowledge
One publication, and unlike API 510 or 653 there is no partial scope: the whole document is examinable.
API RP 571, Damage Mechanisms Affecting Fixed Equipment in the Refining Industry
3rd edition, 2020
- The entire document
How to prepare
One document, and all of it counts
API 510 rewards knowing which parts of which standards are in scope. API 571 does not: the Body of Knowledge is the whole of RP 571, so there is nothing to narrow down and no effectivity sheet to work from. The work is coverage — every damage mechanism, not the fifteen that appear in the 510 list.
Learn each mechanism by its five facts
RP 571 describes every mechanism the same way: affected materials, critical factors, affected units or equipment, appearance or morphology, prevention or mitigation, and inspection and monitoring. Questions follow that structure, so learning a mechanism means being able to answer all six for it rather than recognising its name.
Closed book means recall speed
195 minutes for 110 questions is a little under two minutes each with nothing to look up. Temperature thresholds, susceptible alloys and the distinguishing appearance of similar mechanisms have to be recallable, not derivable. Confusable pairs are where the marks go — caustic versus amine cracking, chloride versus polythionic acid SCC, sulfidation versus naphthenic acid corrosion.
Do not study it as if it were the 510 exam
There is no open-book part, no calculation of remaining life against a code, and no WPS review. Practice that mixes those in is practising for a different paper. Time spent on ASME VIII-1 or PCC-2 does not come back on this one.
PRACTISING WITH ASSETRONX
The API 571 bank has 2,425 questions — 2,425 closed-book and 0 open-book — each with its answer, the reasoning and the clause it comes from, plus 3 full mock exams timed like the real day. Questions are grouped by publication, so you can work through one document at a time.
| PUBLICATION | CLOSED BOOK | OPEN BOOK |
|---|---|---|
| API.571 | 2,425 | 0 |
Questions
How many questions are on the API 571 exam?
110: 100 scored questions and 10 unscored pretest questions that API is trialling.
Is the API 571 exam open book?
No. API states that all questions are multiple-choice and closed-book, and that paper and reference materials are not allowed into the exam.
Which edition of API RP 571 is examined?
The Body of Knowledge is the entire API RP 571, 3rd edition (2020). API publishes a Body of Knowledge document for each exam year; check it against your exam date.
Do I need API 510, 570 or 653 first?
No, but holding a current one of the three qualifies you automatically. Without one, qualification is by education plus petrochemical experience acquired within the last 10 years — one year with a BS, two with a two-year degree, three with a high school diploma, five or more with no formal education.
What is the passing score for API 571?
API says the exam has a set passing scaled score and does not publish the figure. Any specific number you find on a preparation site is not from API.
How long is API 571 certification valid?
Three years, after which it has to be recertified.
Sources
Checked on 27 September 2026. API updates these documents for each exam window; if anything here differs from API's current documents, API is right.
AssetronX is an independent exam preparation provider and is not affiliated with or endorsed by the American Petroleum Institute. API 571 is a certification of the American Petroleum Institute.