- What the Authorized Inspector Commission Exam Actually Tests
- The 12-Heading Outline as Your Study Map
- Building Your Reference Library
- Where Candidates Lose Points: Design, Fabrication and Welding
- NDE, Testing, Heat Treatment and Calibration
- Data Reports, Stamping and Record Retention
- Sequencing the Domains Across Your Prep Weeks
- Course Attendance and Exam Logistics
- Practicing Code-Based Questions the Right Way
- Frequently Asked Questions
- The exam outline (NB-331-NC Revision 6) has 12 numbered headings, and the National Board publishes no percentage weights for them.
- The issuer confirms 85 questions and attendance at the AI Commission course with a passing examination.
- Required references: ASME Sections I, IV, V, VIII Division 1, IX; B31.1; QAI-1; RCI-1/NB-263.
- Design, materials and fabrication cover the most detailed outline content, so budget the most study hours there.
What the Authorized Inspector Commission Exam Actually Tests
The National Board Authorized Inspector Commission (AI) is issued by The National Board of Boiler and Pressure Vessel Inspectors. It is not a general knowledge test about boilers. It measures whether you can apply the ASME Boiler and Pressure Vessel Code and the National Board's inspection rules to real construction situations: reading a requirement, finding it in the right Section, and deciding whether a given design, material, weld, test or record complies.
That distinction shapes everything about how you should prepare. Candidates who succeed treat the Code books as working tools rather than texts to memorize. If you are still sorting out the basics of the credential, our overview pages on what AI certification is and the AI requirements and eligibility rules are good starting points before you commit to a study schedule.
The issuer's examination information confirms the exam consists of 85 questions and that candidates attend the AI Commission course and take a passing examination. The exact timer, the current fee and the numerical pass mark are not something this article can state with confidence, so confirm them directly with the National Board. For a fuller discussion of how scoring works, see what you need to pass, and for the cost side, the pricing breakdown.
The 12-Heading Outline as Your Study Map
No percentage weights are published, so you cannot rank domains by exam share. What you can do is rank them by how much detailed outline content each carries. Design, materials and fabrication are densely itemized; others are shorter but still testable. Here is the full structure at a glance:
| Domain | Core focus | Primary references |
|---|---|---|
| 1. Responsibilities and Duties of the AI | Roles of authorized inspection agencies, supervisors and inspectors | RCI-1, ASME QAI-1 |
| 2. Boiler and Pressure Vessel Types and Terminology | Identifying boiler and vessel types and their parts | Sections I, IV, VIII-1 |
| 3. Code Structure and Content | Navigating the ASME BPVC and related requirements | BPVC structure |
| 4. Quality Control System | Quality control requirements per construction type | Sec. I App. A-301, Sec. IV App. F, Sec. VIII-1 App. 10 |
| 5. Design | Shells, heads, openings, stays, flanges, efficiencies | Sections I, IV, VIII-1; B31.1 |
| 6. Materials | Material rules, markings, repair, certifications | Construction sections |
| 7. Fabrication | Forming, tolerances, welding, qualification, repair | Sections I, IV, VIII-1, IX |
| 8. Nondestructive Examination | When required, methods, qualifications, reports | Section V and construction sections |
| 9. Testing and Heat Treatment | Impact testing, PWHT, pressure tests | Construction sections |
| 10. Calibration of M&TE | Frequencies, methods, tolerances, records | Quality control requirements |
| 11. Data Reports and Stamping | Reports and stamping by construction type | Construction sections |
| 12. Record Retention | Retention rules under Sections I, IV, VIII | Sections I, IV, VIII-1 |
For a deeper walk through each heading, our complete guide to all 12 content areas expands on what each domain covers.
Building Your Reference Library
The required references define the universe of testable material. Before you study a single domain, assemble the full list and learn what each document is for:
- ASME Section I: power boilers, including the quality control appendix A-301.
- ASME Section IV: heating boilers, including Appendix F for quality control.
- ASME Section V: nondestructive examination methods and qualification.
- ASME Section VIII, Division 1: pressure vessels, including Appendix 10 for quality control.
- ASME Section IX: welding and brazing qualifications.
- ASME B31.1: power piping, relevant to boiler external piping.
- ASME QAI-1: qualifications for authorized inspection.
- RCI-1 / NB-263: the National Board's rules for authorized inspection agencies and their personnel.
Where Candidates Lose Points: Design, Fabrication and Welding
If you want to understand how hard the exam really is, look at the length of the Design and Fabrication headings. They are the most heavily itemized parts of the outline, and they demand calculation-adjacent reasoning rather than recall.
Domain 5: Design
You must understand how power boilers, heating boilers, external piping and vessels are designed under their respective Code sections.
- Shells and drums, piping, headers and nozzles
- Formed heads and flat heads
- Braced and stayed surfaces
- Weld sizes and nozzle reinforcement
- Preformed and prefabricated pressure parts
- Flanges, joint efficiencies and ligament efficiency
The trap here is treating design as pure formula work. Questions tend to ask whether a configuration meets a requirement, so you need to know which paragraph governs and which variables feed into it. Joint efficiency and ligament efficiency in particular reward careful reading of definitions and limits.
Domain 6: Materials
Material rules live in the construction sections, and the outline expects you to apply them.
- Construction-section material rules for pressure and nonpressure parts
- Product-form tolerances
- Markings and marking methods
- Use of non-ASME standards
- Repair of defective material
- Material certifications
Domain 7: Fabrication
This is the broadest heading, combining forming, tolerances and welding.
- Cutting and edge preparation; cold-forming limits
- Out-of-roundness limits for cylindrical, conical and spherical shells
- Formed-head tolerances; lug and fitting attachment
- Holes for screwed or threaded stays and tubes
- Welding responsibilities and processes; procedure, welder and operator qualifications (Section IX)
- Surface cleaning, alignment tolerances, spin holes, finished joints and fillet welds
- Defect repair, peening and surface weld-metal buildup
Fabrication questions often hinge on who is responsible for a step as well as what the limit is. Tie your Domain 7 study back to Domain 1: the inspector's duties determine what you verify versus what the manufacturer certifies.
NDE, Testing, Heat Treatment and Calibration
These three headings are shorter than Design or Fabrication, but they are compact and factual, which makes them efficient points if you prepare well.
Domain 8: Nondestructive Examination
Know when NDE is required, which methods are permitted, and the advantages and limitations of each method. Be ready for questions on procedure and personnel qualification and on what must appear in a report. Section V is your anchor, but the construction sections decide when examination is mandatory, so study the two together.
Domain 9: Testing and Heat Treatment
This heading covers impact testing, heat treatment and pressure tests, including exemptions and alternatives. The exemptions are where questions concentrate: the exam is likely to probe whether a particular case is exempt, and what alternative applies when it is not. Build a short table of conditions and outcomes for each construction section.
Domain 10: Calibration of Measurement and Test Equipment
The outline calls for knowledge of calibration frequencies, methods, tolerances, master standards, identification and records for both working and master measurement and test equipment. Many candidates skim this because it feels administrative. That is a mistake: the hierarchy of master versus working equipment and the associated records is exactly the kind of structured detail that produces clean right-or-wrong questions.
Key Takeaway
Compact domains like calibration and record retention are the cheapest points on the exam. Master them early so your remaining time goes to the denser design and fabrication material.
Data Reports, Stamping and Record Retention
Domains 11 and 12 close out the lifecycle of a pressure-retaining item. Data reports and stamping vary by construction type, so a power boiler, a heating boiler and a Section VIII, Division 1 vessel each have their own requirements. The risk is blending them together. Study each construction type separately, then compare.
Record retention works the same way: the outline specifies retention under Sections I, IV and VIII, and the details differ by section. A side-by-side chart of what is kept, by whom, and for how long under each section is one of the most useful single study aids you can make. Our one-page review of must-know facts shows how to condense this kind of comparison.
Sequencing the Domains Across Your Prep Weeks
Rather than a generic schedule, order your study by dependency. Duties and terminology come first because they give context to everything else; design and fabrication need the longest runway; the short administrative domains fit well in review weeks.
Foundations
- Domains 1-3: duties under RCI-1 and QAI-1, vessel and boiler terminology, Code structure
- Tab every required reference
Quality control and materials
- Domain 4: Sec. I App. A-301, Sec. IV App. F, Sec. VIII-1 App. 10
- Domain 6: material rules, markings, certifications
Design
- Domain 5: shells, heads, openings, stays, flanges, efficiencies
- Work through each construction section separately
Fabrication and welding
- Domain 7 with Section IX alongside
- Tolerances, out-of-roundness, repair, peening
Verification domains
- Domains 8-10: NDE, testing and heat treatment, calibration
Paperwork and full review
- Domains 11-12, then mixed-domain practice under timed conditions
Adjust the length to your background. An experienced pressure-vessel or boiler professional may compress the early weeks, while someone newer to Code work should extend Weeks 3-6. Check exam dates and scheduling before locking in a timeline.
Course Attendance and Exam Logistics
The pathway to the commission involves attending the AI Commission course and passing an examination, according to the issuer. Treat the course as part of your preparation, not a substitute for it. Arrive having already worked through the references so that the instruction clarifies rather than introduces material.
- Confirm the numbers that are unverified here: the current fee, the exam timer and the numerical pass mark should come directly from the National Board.
- Check eligibility first: the requirements guide explains prerequisites so you do not invest in preparation before you qualify.
- Know your employer's role: authorized inspection agencies are the typical sponsors, so the hiring side matters; see AI jobs and earnings analysis for the career context, and the ROI discussion if you are weighing the investment.
Practicing Code-Based Questions the Right Way
Because the exam is built on application of the Code, good practice mirrors that task. When you miss a question, do not just note the answer: find the exact paragraph, table or appendix that supports it, and write down the path you used to reach it. Over time you build a mental map of where requirements live.
- Start each session by naming the domain and the governing reference.
- Answer a block of questions, then audit every miss against the source text.
- Keep an error log grouped by domain so patterns surface, such as confusing Section I with Section VIII, Division 1 requirements.
- Finish with mixed-domain sets, because the real exam will not announce which heading a question belongs to.
Our practice questions at the main practice test site are built for exactly this loop, and you can pair them with the broader study guide for reference. If you want to gauge readiness against real outcomes, read the discussion of pass rate data with an eye toward what is and is not publicly reported.
Key Takeaway
The differences between construction sections are the most common source of wrong answers. When you study any topic, always ask: does this rule differ for power boilers, heating boilers and Section VIII, Division 1 vessels?
Frequently Asked Questions
The issuer's examination information confirms 85 questions. The exact timer, current fee and numerical pass mark should be verified directly with the National Board, since they are not confirmed here.
No. The detailed outline, NB-331-NC Revision 6, lists 12 numbered headings but publishes no percentage weights. Plan your time by the amount of detailed content under each heading rather than by an assumed exam share.
ASME Sections I, IV, V, VIII Division 1 and IX; ASME B31.1; QAI-1; and RCI-1/NB-263. These define the scope of testable material across all 12 domains.
Design, Materials and Fabrication carry the most itemized detail in the outline, so they typically need the longest preparation. Shorter domains such as Calibration and Record Retention are still testable and are efficient to master early.
No. The introductory summary groups content differently and does not replace the detailed hierarchy. Use the 12-heading detailed outline as your study map.