200+ Free API 653 Practice Questions

Pass your API 653 Aboveground Storage Tank Inspector exam on the first try — instant access, no signup required.

✓ No registration✓ No credit card✓ No hidden fees✓ Start practicing immediately

200+ Questions

100% Free

1 / 200

Question 1

Score: 0/0

API 653 primarily applies to which equipment?

In-service aboveground welded storage tanks built for atmospheric or low-pressure service

Underground fuel tanks regulated only as environmental release systems

Pressurized spheres and bullets designed under pressure-vessel rules

Portable tote tanks used only for transportation

to track

2026 Statistics

Key Facts: API 653 Exam

170

Total Questions

140 scored + 30 pretest

110 / 60

Closed / Open Book

API 653 exam page

400 / 500

Scaled Passing Score

API exam scoring page

$875 / $1,125

2026 Exam Fee

API schedules & fees

1-5 years

Experience Pathways

Depends on education

3 years

Certification Term

API recertification cycle

As of March 12, 2026, API's current API 653 exam is still a 170-question in-person CBT with 110 closed-book questions, 60 open-book questions, and a 400 scaled passing score. The March 2026 to November 2026 Publications Effectivity Sheet updates API RP 575, API RP 576, API RP 651, selected API RP 571 damage mechanisms, and lists API 653 addenda and errata that now drive the current exam references. API publishes the official Body of Knowledge and the 110/60 closed-book versus open-book structure, but it does not publish a public percentage-by-domain blueprint, so the percentages below are practice-weighted estimates based on the current BOK emphasis.

Sample API 653 Practice Questions

Try these sample questions to test your API 653 exam readiness. Each question includes a detailed explanation. Start the interactive quiz above for the full 200+ question experience with AI tutoring.

1API 653 primarily applies to which equipment?

A.In-service aboveground welded storage tanks built for atmospheric or low-pressure service

B.Underground fuel tanks regulated only as environmental release systems

C.Pressurized spheres and bullets designed under pressure-vessel rules

D.Portable tote tanks used only for transportation

Explanation: API 653 is the in-service inspection, repair, alteration, and reconstruction standard for aboveground welded storage tanks in atmospheric or low-pressure service. It is not the governing standard for pressure vessels, underground tanks, or transport containers.

2What is the main purpose of an external inspection on an API 653 tank?

A.To directly measure the entire floor underside for corrosion without any other methods

B.To qualify welders and procedure specifications for future repairs

C.To rerate the tank automatically to a higher fill height

D.To assess visible condition of the shell, roof, foundation, appurtenances, and evidence of distress while the tank may remain in service

Explanation: External inspection focuses on the tank's visible condition, including shell distortion, coating breakdown, leaks, roof condition, settlement clues, and attached items. It does not replace all internal floor assessment or automatically change the tank's design limits.

3Which inspection activity gives the inspector the best direct view of the tank bottom and shell-to-bottom weld from inside the vessel?

A.A review of old nameplate data only

B.A dike-drainage inspection from outside the shell

C.An internal inspection after the tank has been taken out of service, cleaned, and made safe for entry

D.A routine visual walk-around while the tank is full

Explanation: Internal inspection is the direct way to examine the floor, floor welds, lower shell interior, sludge zones, and lining condition. External walk-arounds and records reviews are important, but they do not expose the inside surface of the tank bottom.

4Who is primarily responsible for maintaining the tank's records and implementing the owner-user inspection program?

A.The dike-construction contractor

B.The owner-user organization

C.The welder who performed the last repair

D.Any NDE technician who last visited the site

Explanation: API 653 places the inspection program and recordkeeping responsibility on the owner-user. Contractors and inspectors contribute records and technical input, but the owner-user remains responsible for the overall program.

5What is the authorized inspector's core role under API 653?

A.To determine whether the tank and related work are acceptable under the standard

B.To serve as the tank's day-to-day operator

C.To replace the owner-user's recordkeeping system

D.To approve electrical one-line diagrams for the whole facility

Explanation: The authorized inspector makes inspection and acceptability determinations within the scope of API 653. The role is technical and judgment-based, not a substitute for operations management or unrelated engineering disciplines.

6Before a person enters a tank for internal inspection, what must happen first?

A.The tank should stay connected to active product lines for ventilation

B.A hydrotest should be run while personnel are inside to check leaks

C.Only the floating roof drains need to be opened

D.The tank must be isolated, cleaned as needed, tested for safe entry conditions, and entered under the site's confined-space controls

Explanation: Internal tank entry is a confined-space activity that requires isolation, gas testing, permitting, and site safety controls before personnel entry. Safe preparation comes before inspection work.

7Why is reviewing prior thickness data useful before a new inspection?

A.It guarantees the tank can be rerated upward

B.It replaces the need to review the current service conditions

C.It helps the inspector trend corrosion rates and judge how deterioration is progressing over time

D.It eliminates the need for any new field measurements

Explanation: Prior thickness data lets the inspector compare metal-loss history, estimate corrosion rates, and focus on areas that are worsening. Trending is a key part of interval planning and integrity evaluation.

8What tank area commonly deserves close attention during internal inspection because water and sludge often accumulate there?

A.The handrail paint on the stair landing only

B.The tank bottom, especially low spots and the shell-to-bottom region

C.The exterior stair treads only

D.The dike wall cap only

Explanation: Water, sludge, and product contaminants often collect on the floor, creating corrosion risk, especially near low areas and the shell-to-bottom region. That makes the bottom one of the most critical areas during internal inspection.

9Which condition most strongly suggests corrosion under insulation on a tank shell?

A.Damaged insulation jacketing with moisture entry points and staining at seams or penetrations

B.A clean, dry shell with newly installed intact insulation

C.An accurate level gauge reading

D.A recently calibrated overfill alarm

Explanation: CUI often develops where water can get behind damaged jacketing, especially at seams, supports, and penetrations. Staining, wet insulation, and deteriorated cladding are common warning signs.

10Why are pressure and vacuum vents included in external inspection scope?

A.Because they are used to measure shell thickness directly

B.Because they replace the need for overfill protection systems

C.Because they are only decorative appurtenances with no integrity function

D.Because blocked or malfunctioning vent devices can expose the tank roof and shell to damaging pressure or vacuum conditions

Explanation: Venting devices protect the tank from abnormal internal pressure and vacuum that can damage the roof or shell. Inspectors therefore look for blockage, corrosion, sticking parts, and obvious malfunction.

About the API 653 Exam

API 653 is the core API Individual Certification Program for inspectors responsible for in-service aboveground storage tanks. The exam tests inspection planning, corrosion and damage recognition, thickness and interval calculations, repair and alteration decisions, welding and NDE oversight, settlement evaluation, and documentation under API 653 and the related open-book references on the current effectivity sheet.

Assessment

170 multiple-choice questions: 110 closed-book + 60 open-book (140 scored + 30 pretest)

Time Limit

7.5-hour exam day (2.75 hours closed-book, 45-minute lunch, 3.75 hours open-book)

Passing Score

400 scaled score on API's 200-500 scale

Exam Fee

$875 API member / $1,125 nonmember (American Petroleum Institute (API) / Prometric)

API 653 Exam Content Outline

24% practice weight

Inspection Scope, Planning, and Tank Components

API 653 scope, tank types and terminology, owner-user and authorized inspector roles, inspection preparation and safety, records review, external versus internal inspection, and practical checks on shells, roofs, bottoms, nozzles, foundations, and attached items.

20% practice weight

Damage Mechanisms, Materials, and Protection

Atmospheric, soil-side, underside, and product-side corrosion; brittle-fracture risk and material toughness; cathodic protection; tank-bottom linings; and the specific API RP 571 mechanisms called out on the current effectivity sheet.

22% practice weight

Thickness, Remaining Life, and Integrity Calculations

Corrosion-rate and remaining-life calculations, inspection interval logic, shell and bottom evaluation, pitting and localized loss assessment, settlement interpretation, joint efficiency, and impact-testing triggers that inspectors need to judge code compliance.

16% practice weight

Repairs, Alterations, Reconstruction, and Welding

Repair-versus-alteration decisions, reconstruction concepts, replacement plates, hot taps, patch plates, API 650 and API 653 welding rules, WPS/PQR/WPQ control, and repair-organization or authorized-inspector responsibilities.

10% practice weight

NDE and Testing

Radiographic, liquid penetrant, magnetic particle, and ultrasonic examination principles, when each method is appropriate for tank work, and how leak tests, hydrotests, and related post-repair testing decisions fit the API 653 workflow.

8% practice weight

Relief Devices, Settlement, and Documentation

Pressure and vacuum venting basics, settlement monitoring, nameplates, inspection reports, repair records, and the documentation trail needed to support in-service fitness decisions and future inspection planning.

How to Pass the API 653 Exam

What You Need to Know

Passing score: 400 scaled score on API's 200-500 scale
Assessment: 170 multiple-choice questions: 110 closed-book + 60 open-book (140 scored + 30 pretest)
Time limit: 7.5-hour exam day (2.75 hours closed-book, 45-minute lunch, 3.75 hours open-book)
Exam fee: $875 API member / $1,125 nonmember

Keys to Passing

Complete 500+ practice questions
Score 80%+ consistently before scheduling
Focus on highest-weighted sections
Use our AI tutor for tough concepts

API 653 Study Tips from Top Performers

1Memorize corrosion-rate, remaining-life, shell-evaluation, and interval-setting formulas well enough to work them closed-book without relying on the references.

2Study the March 2026 Body of Knowledge and Publications Effectivity Sheet together so you know both what is testable and where those rules live during the open-book portion.

3Practice classifying findings into repair, alteration, reconstruction, or continued service because many API 653 questions start with that judgment step.

4Build damage-mechanism recognition from API RP 571, especially atmospheric corrosion, bottom-side corrosion, soil-side corrosion, brittle-fracture risk factors, concentration cell corrosion, and ethanol stress-corrosion cracking.

5Treat open-book time as a navigation exam, not a reading exam. Speed comes from knowing which API or ASME reference contains the answer before you sit down at Prometric.

6Review welding and NDE controls together so you can connect WPS/PQR/WPQ requirements with the right examination method and post-repair verification step.

7Do repeated shell, bottom, and settlement problems until you can spot the required formula quickly and keep units consistent.

8Use mixed practice sets after each study block so you can shift quickly from formulas to corrosion scenarios to documentation and code-application questions the way the real exam does.

Frequently Asked Questions

How many questions are on the API 653 exam?

API states that API 653 contains 170 multiple-choice questions, but only 140 are scored. The remaining 30 are pretest items that do not count toward the final result. The exam is split into 110 closed-book questions and 60 open-book questions.

How long is the API 653 exam?

The official API 653 exam day is 7.5 hours long. API breaks that into a short tutorial, 2.75 hours for the closed-book portion, a 45-minute lunch break, and 3.75 hours for the open-book portion.

What score do I need to pass API 653?

API's current exam-scoring page states that Individual Certification Program exams are reported on a 200-to-500 scaled-score scale and that 400 is the minimum passing score. That means you should not treat the exam as a simple raw-percentage cutoff. The better goal is to be consistently strong across calculations, corrosion judgment, welding and NDE controls, and code-application questions.

What references are current for API 653 in 2026?

As of March 12, 2026, the current public API 653 exam materials point to the March 2026 to November 2026 Body of Knowledge and Publications Effectivity Sheet. Those official files list API 653 with addenda and errata plus selected sections of API 650, API RP 571, API RP 575, API RP 576, API RP 651, ASME Section V, and ASME Section IX as the references used for the current exam cycle.

What changed for API 653 in 2026?

The March 2026 to November 2026 effectivity sheet updates several supporting references compared with the earlier cycle. API RP 575 moved to the 5th Edition from September 2024, API RP 576 moved to the 5th Edition from September 2024, API RP 651 moved to the 5th Edition from August 2024, the listed API RP 571 damage mechanisms now include concentration cell corrosion and ethanol stress-corrosion cracking, and the API 653 reference list now includes the February 2025 errata.

Does API publish official domain percentages for API 653?

Not publicly. API publishes the official Body of Knowledge topics and the closed-book versus open-book structure, but it does not publish a public percentage weighting by domain. For study planning, use the current BOK to prioritize inspection fundamentals, corrosion and materials, shell and bottom calculations, welding and repair rules, and open-book code navigation.

Is remote testing available for API 653 in 2026?

No. API's current schedule-exams page specifically notes that API 653 is not available for remote testing. The current certification page also describes the exam as taking place at designated Prometric computer testing centers, so candidates should plan for an in-person administration.

What experience do I need to sit for API 653?

API uses education-and-experience pathways. Candidates with a BS or higher in engineering or technology, or 3 or more years of military technical service, need 1 year of qualifying AST inspection experience; associate-degree or certificate pathways require 2 years; high school requires 3 years; and no formal education requires 5 years. API also states that the qualifying experience must have been gained within the last 10 years under the supervision of an authorized inspection agency or a technically equivalent organization.