Find the applicable BOK
Take the Body of Knowledge for your exam window from api.org, with the publications effectivity sheet published alongside it. The first tells you which topics are in scope, the second which edition of each document the questions are written against. Both are revised: use the pair attached to your window.
- Body of Knowledge
- The topics your exam can cover.
- Effectivity sheet
- The document editions for your window.
- Domain I, calculations: minimum thickness, corrosion rates, remaining life, MAWP.
- Domain II, welding: procedure qualification under ASME IX, weld examination.
- Domain III, NDE: radiography, ultrasonics, magnetic particle and penetrant, under ASME V.
- Domain IV, general practice: inspection programmes, roles, records, API 570 and 574.
- Domain V, specific practice: damage mechanisms, repairs, in-service re-rating.
Map the topics
Work from the domain to the document, not the reverse. Each line of the Body of Knowledge points at a document that settles it: intervals, roles and records in API 570 and 574, degradation in RP 571, repair and welding practice in RP 577 and 578, design and test rules in ASME B31.3, examination methods in BPVC Section V, procedure qualification in Section IX.
| Topic | Reference named in this guide |
|---|---|
| Intervals, roles and records | API 570 and 574 |
| Degradation | RP 571 |
| Repair and welding practice | RP 577 and 578 |
| Design and test rules | ASME B31.3 |
| Examination methods | BPVC Section V |
| Procedure qualification | Section IX |
Then mark each topic for what it demands. Some lines are pure recall, for the closed-book half. Others are navigation: you can look them up on the day, so the skill is speed. A third group is calculation, where neither recall nor lookup helps if the method is not automatic.
Inspection, welding and calculations#
The three groups fail differently. Calculations need the method repeated by hand until the steps come without thinking. Welding and NDE reward knowing which document governs and what the acceptance criteria turn on. The practice domains carry the intervals, responsibilities and thresholds, where memory rather than reading does the work.
Turn the map into practice
Start without preparation
A map is only useful once it is scored. Run a session across all five domains before you start studying, without preparation and without opening anything, and let the result weight your plan. Two domains are usually well behind: those two take your next blocks of study.
Return to the map
After that, work one domain at a time, returning to the map between blocks. We report practice and mock results by Body of Knowledge domain, which makes the comparison possible: look less for a higher score than for the domain where you cannot explain your own mistakes.
Frequently asked questions
What is the API 570 Body of Knowledge?#
It is the published statement of the topics the exam can cover, organised into domains and tied to specific documents. API issues it with the certification programme for a given exam window: it is the right starting point for a study plan.
Does it tell me how heavily each domain is weighted?#
Read the published document for that. We publish no weighting of our own: a percentage breakdown on a third-party page is worth nothing unless it comes from the API text for your window.
Is the Body of Knowledge the same for recertification?#
No. Initial certification and recertification have their own published scopes. Check which applies to you before building a plan: the chapters you need are not identical.
Do I need to read every document in full?#
No. Read for structure first, so you know which document answers which kind of question, then in depth where your diagnostic puts you behind. The open-book half tests navigation, learned by searching.