Part of the expanding PassProfessor catalog: the API 510 Pressure Vessel Inspector examination is API’s in-service pressure vessel credential — 170 questions in a 7.5-hour day at a Prometric test center, split between a closed-book part and an open-book part, passed at a scaled score of 400 on the published 200 to 500 scale. PassProfessor’s API 510 program is in the works, built to the effectivity pins for the September 2026 to May 2027 cycle.
The API 510 credential is the pressure vessel inspector’s authorization: it certifies that an inspector can inspect, rate, repair, and rerate in-service pressure vessels under the API 510 code and the reference publications API pins to the examination. PassProfessor’s API 510 program is in the works as part of the expanding PassProfessor catalog, built on API’s published Body of Knowledge and Publications Effectivity Sheet for the September 2026, January 2027, and May 2027 examinations, and organized around what that Body of Knowledge tests — integrity calculations, welding qualification review, nondestructive examination, damage mechanisms, and the code itself.
Which examination is this?
This page covers one credential only: the API 510 Pressure Vessel Inspector certification, administered by the American Petroleum Institute (API) through its Individual Certification Programs (ICP). It is not preparation for API 570 (piping) or API 653 (storage tanks): each API program has its own Body of Knowledge and pinned editions, stated here and in the companion guide. Material built to the ASME BPVC 2023 Edition or older editions is superseded: the current cycle pins the ASME BPVC 2025 Edition.
What will the program cover?
1,500 original practice questions. The program holds 1,500 original practice questions across the nine areas of the blueprint below, written from scratch against API’s published Body of Knowledge and effectivity sheet. None is an actual examination item, a recalled item, or another provider’s material, and no question asks you to recite a clause, paragraph, or table number: the examination tests applying the pinned publications to inspection data, records, and situations, and the practice tests the same application.
An explanation for every question. Every practice question carries an explanation — an explanation for every question in the bank — so a miss teaches the rule, the computation, or the record feature that decided the answer.
Results you can read by area. Practice is organized by the blueprint’s areas, so a thin area — calculations, say, or damage mechanisms — shows while there is still time to repair it, instead of hiding inside an overall score.
Timed practice at the real sitting’s shape. Sustained timed practice modelled on the real sitting trains pacing across a long examination day.
One disclosure belongs at the front: API publishes no weighting for this examination. The nine areas below and their counts are a PassProfessor allocation, set in proportion to the emphasis in API’s Body of Knowledge — never API’s weighting.
What are the verified facts of the real exam?
| Fact of record | Detail |
|---|---|
| Credential | API 510 Pressure Vessel Inspector, administered by API’s Individual Certification Programs (ICP); the program is ANSI-accredited under ISO/IEC 17024 |
| Format | 170 questions: 140 scored and 30 unidentified pretest questions. 110 closed-book questions and 60 open-book questions |
| The exam day | 7.5 hours in total: a short tutorial, 165 minutes closed-book, a 45-minute lunch break, and 225 minutes open-book — 390 minutes of testing time |
| Delivery | Computer-based at Prometric test centers, in person only. API states expressly that this examination is not available for remote testing |
| References on the day | Papers, notes, and books are not allowed in the test center. During the open-book part only, PDF documents of the pertinent codes and standards are provided on the exam computer, limited to the effectivity sheet’s sections |
| Item formats | The majority of questions are multiple-choice, single-answer. API is gradually adding Alternative Item Types — such as drag and drop, ordered response, multiple response, and matching — into its examinations |
| Scoring | Prometric reports a scaled score on a scale from 200 to 500. The passing scaled score is 400, as API publishes it. Reports show the scaled score, not the number answered correctly |
| Eligibility | Education plus pressure-vessel experience acquired within the last 10 years, documented and verified by API — see the eligibility section below. No training course is required |
| Current cycle | Body of Knowledge and effectivity sheet for the September 2026, January 2027, and May 2027 examinations. The September 2026 window has run; the remaining windows are January 2027 and May 2027 |
| Application | Apply through API’s ICP Portal. An application is valid for 6 months from the first exam date requested. After approval, API issues an Exam Authorization with an Eligibility ID; the candidate books a Prometric seat in the approved window |
| Examination fee | Confirm the current fee on API’s ICP Schedules & Fees page at api.org when you apply. This page prints no fee figure |
| Keeping the credential | Certification runs in 3-year terms — see below |
How does the practice map to the Body of Knowledge?
API’s Body of Knowledge has five sections: thickness measurements, inspection intervals and vessel integrity; welding procedure and qualification evaluation; nondestructive examination; practical knowledge — general; and practical knowledge — specific. The practice bank divides that material into nine areas.
| Practice area | Practice questions |
|---|---|
| Thickness, Intervals and Vessel Integrity Calculations | 320 |
| API 510 Inspection, Rating, Repair and Alteration | 210 |
| Welding Procedure and Qualification Evaluation | 180 |
| Nondestructive Examination | 170 |
| Damage Mechanisms (API RP 571) | 170 |
| Inspection Practices and Pressure-Relieving Devices | 120 |
| Materials, Fabrication and Practical Knowledge | 120 |
| Repair Methods (ASME PCC-2) | 110 |
| Welding Processes, Metallurgy and Material Verification | 100 |
| Total | 1,500 |
What do the thickness, interval, and integrity calculations cover?
The computational core: corrosion rates, metal loss, remaining allowance and remaining life; interval determination; joint efficiencies; static head and the difference between a part’s maximum allowable working pressure and the vessel’s; required thickness and maximum allowable working pressure for shells and heads; pressure-test pressures; and impact-testing requirements. Questions are oriented to existing vessels under internal pressure, in both US customary and SI units. External-pressure and nozzle-reinforcement calculations sit outside the tested families.
Remaining life is the hinge number: most interval and repair decisions turn on computing it correctly, in the units the stem gives.
What does the API 510 code area cover?
The code itself, applied: how inspection is organized and its types; planning, records, and reports; repairs and alterations; rerating; pressure testing after repairs; and corrosion and minimum-thickness evaluation. This is where the closed-book skill is tested most directly.
Where API 510 and ASME Section VIII rules overlap on welding, API 510 takes precedence — record-review items key accordingly.
What does welding procedure and qualification evaluation cover?
Reading welding records as an inspector reviews them before a repair is approved: procedure specifications, qualification records, and welder qualifications checked for compliance; essential and nonessential variables and the mechanical tests a qualification requires; processes, filler metals, and base-metal limits; and the general welding requirements in ASME Section VIII and API 510. Record review is bounded — one process per record set, on a defined set of base-metal groups.
A record can be complete, signed, and still wrong: the deciding feature is usually a variable that outruns its supporting qualification.
What does nondestructive examination cover?
The methods the pinned Section V articles govern: the general requirements article; radiographic, liquid penetrant, and magnetic particle examination (yoke and prod techniques only); ultrasonic thickness measurement; and the general requirements in ASME Section VIII and API 510. Acoustic emission, eddy current, and motion radiography are out of scope.
Match the method to the discontinuity and the material: a sound method for the wrong condition is the distractor.
What do damage mechanisms cover?
API RP 571 as the effectivity sheet pins it: the terms and definitions section, and fifteen named mechanisms only — among them amine stress corrosion cracking, atmospheric corrosion, caustic corrosion and caustic stress corrosion cracking, chloride stress corrosion cracking, corrosion under insulation, erosion and erosion-corrosion, high-temperature hydrogen attack, naphthenic acid corrosion, sulfidation, and wet hydrogen sulfide damage. No other mechanism is on this examination.
Mechanism items turn on the combination: material, environment, temperature, and stress together name the mechanism.
What do inspection practices and pressure-relieving devices cover?
API RP 572, inspection practices for pressure vessels, and API RP 576, inspection of pressure-relieving devices — how vessels and their protective devices are examined in the field, and what findings require action.
A relief device is part of the vessel’s integrity case, not an accessory: findings on the device carry the same weight as findings on the shell.
What do materials, fabrication, and practical knowledge cover?
The practical knowledge underneath the code work: types of process corrosion and deterioration; modes of mechanical, thermal, and high-temperature deterioration; materials and fabrication problems; the ASME Section VIII construction requirements behind inspection decisions; welding in general practice; and maintenance inspection safety practices.
Practical items reward connecting the finding to its cause: the same wall loss reads differently by deterioration mode.
What do repair methods cover?
ASME PCC-2 as the effectivity sheet pins it — fourteen listed articles only, each with its appendices: scope and repair concepts; insert plates, weld buildup, weld overlay, and fillet-welded patches; alternatives to postweld heat treatment, in-service welding, and welded hot taps; chromium-molybdenum repair welding and flaw excavation and weld repair; flange and heat exchanger repair; and pressure and tightness testing.
The repair question is never only whether a method exists: it is whether it fits this vessel, this damage, and these conditions.
What do welding processes, metallurgy, and material verification cover?
API RP 577, welding processes, inspection, and metallurgy, across the whole document as pinned; and API RP 578, the material verification program — positive material identification, so the material in the vessel is the material the design assumes.
A material verification failure is an integrity failure found early — identification questions carry thickness-question seriousness here.
How is API 510 scored?
API publishes the standard as a scaled score. Prometric uses a scale from 200 to 500 for API’s Individual Certification Programs examinations, and the passing scaled score for the API 510 examination is 400. A scaled score is not a percentage, and API publishes no percentage pass mark, no raw pass mark, and no number-correct threshold. API’s equating process adjusts for form difficulty, so the number of correct answers corresponding to 400 may differ slightly between forms while the scaled standard represents the same minimum knowledge.
Who can take this exam, and what does it certify?
Qualification combines education with pressure-vessel experience acquired within the last 10 years while employed by, or under contract with, an authorized inspection agency as defined in API 510; it must be documented on the application, and API verifies it after submission. As API publishes the table: a bachelor’s degree or higher in engineering or technology — or 3 or more years of military service in a technical role — requires 1 year of API 510 inspection activity. A 2-year degree or certificate in engineering or technology — or 2 years of military service in a technical role — requires 2 years of design, fabrication, repair, operation, or inspection of pressure vessels, including 1 inspection year. A high school diploma requires 3 years on the same terms; with no formal education, 5 or more years, including the same inspection year. No training course is required, and API does not endorse test-preparation classes. The credential is awarded by API alone; PassProfessor does not certify inspectors and does not enrol candidates for the official examination.
How do inspectors keep the credential?
Certification is valid for a 3-year term. At each recertification the inspector shows two things: work — a minimum of one fifth of working time over the most recent 3-year period spent performing or supervising pressure vessel inspection activities as described in API 510 (inspectors not actively engaged must take the full examination again); and continuing professional development — 24 CPD hours per cycle, relevant to inspection and mechanical integrity, across at least two activity categories, with proof uploaded to the Portal. Every 6 years the inspector must also pass an online, open-book web quiz on code changes: 25 questions in 4 hours, which may be paused up to three times, available from 90 days before expiry through a 90-day grace period after it. Recertification is applied for online in the ICP Portal in the same window. Since June 2025, API issues its ICP certifications digitally.
What makes this test demanding?
Three features make this examination harder than a single-code test. First, the two-part structure: 110 closed-book questions test what an inspector is expected to know cold, then 60 open-book questions test how well the same inspector can find and apply detailed information under time pressure, in a provided-PDF environment limited to the effectivity sheet’s sections. Second, the calculation load: corrosion rates, remaining life, intervals, joint efficiencies, and required thickness are worked, not recalled, in both unit systems. Third, the breadth of the pinned library — the API 510 code, five recommended practices, three ASME documents — each included only to a stated depth the candidate must know.
An honest note on format
Every PassProfessor practice question is a single-answer, four-option item. The real examination’s majority format is also multiple-choice, single-answer — but API is gradually adding Alternative Item Types, the sitting splits into closed-book and open-book parts, and the open-book part runs in Prometric’s provided-PDF environment, which practice here does not reproduce. Practice builds the knowledge and calculation skills the Body of Knowledge requires; it does not reproduce the examination’s delivery. Practice results are a study gauge, not a prediction of a scaled score.
How should you use this page while the program is in the works?
- Join the notify list today. Enrollment is not open yet, and the notify list is how you hear the moment it is. While you wait, read the exam guide — it walks the Body of Knowledge area by area and sets out the pinned editions and scoring in full.
- Confirm your eligibility window now. The education-and-experience table above decides who may sit; check your documented experience against it early.
- When the program opens, survey every area first. Early practice should touch each area, so your first picture of yourself is honest.
- Drill the area that costs you. Let results, not preferences, set the next block of study.
- Finish with timed, mixed practice. Sit full timed practice at the real sitting’s pace, in both styles, and test when practice is consistently strong.
Frequently asked questions
How many questions are on the API 510 exam, and how long is it? 170 questions in a 7.5-hour day: 140 scored and 30 unidentified pretest questions, split into 110 closed-book questions in 165 minutes and 60 open-book questions in 225 minutes, with a 45-minute lunch break between the parts.
What score passes the API 510 exam? A scaled score of 400 on Prometric’s 200 to 500 scale, as API publishes it. A scaled score is not a percentage; API publishes no percentage pass mark and no number-correct threshold, and the number of correct answers corresponding to 400 may differ slightly between forms.
Can I take the API 510 exam from home? No. API states expressly that this examination is not available for remote testing; it is taken in person at a Prometric test center.
What references can I use during the exam? None of your own — papers, notes, and books are not allowed in the test center. During the open-book part only, PDF documents of the pertinent codes and standards are provided on the exam computer, limited to the effectivity sheet’s sections.
Which editions does the current exam test? The editions pinned on the effectivity sheet for the September 2026 to May 2027 cycle — including the ASME BPVC 2025 Edition and API 510, 11th Edition with its errata. The companion guide lists every pinned edition.
Does API publish how the exam is weighted by topic? No. API publishes no weighting, percentage, or per-topic question count. The area counts on this page are a PassProfessor allocation of the practice bank, set in proportion to the Body of Knowledge’s emphasis — they are not API’s weighting.
What experience do I need to qualify? Education plus pressure-vessel experience acquired within the last 10 years with an authorized inspection agency, documented and verified by API: from 1 year with an engineering or technology degree, up to 5 or more years with no formal education.
Are these the real exam questions? No. Every question in the program is an original PassProfessor practice question written to API’s published Body of Knowledge. API does not release its examination questions.
Does the practice match the real exam’s format exactly? No, and this page does not claim that it does. Practice items are single-answer, four-option questions in a single sitting; the real examination also includes Alternative Item Types being added gradually, and splits into two parts in Prometric’s provided-PDF environment.
What does the exam cost? Confirm the current fee on API’s ICP Schedules & Fees page at api.org when you apply. This page prints no fee figure.
When will enrollment open? The program is in the works. Join the notify list on this page and we will email you when enrollment opens.
Disclaimer
PassProfessor is an independent exam-preparation provider; this program is not endorsed by, affiliated with, or sponsored by the American Petroleum Institute (API). This program is examination preparation only: the details on this page are drawn from the official sources recorded in the companion guide and are current as of November 2026; API’s official publications govern if anything here differs from them. The credential is awarded by API alone; this program confers no credential.