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API Inspector Certification · Last updated November 2026

API 570 Piping Inspector Exam: free practice test

The API certification exam for in-service piping inspectors, based on API 570, ASME B31.3, ASME B16.5 and the other documents on the effectivity sheet. Exam windows run in late January to February, June and October. The February and June 2027 exams use API 570 5th Edition (2024), B31.3-2024 and B16.5-2020.

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About the API 570 exam

The API certification exam for in-service piping inspectors, based on API 570, ASME B31.3, ASME B16.5 and the other documents on the effectivity sheet. Exam windows run in late January to February, June and October. The February and June 2027 exams use API 570 5th Edition (2024), B31.3-2024 and B16.5-2020.

What's on the exam

API 570
Corrosion Rates, Remaining Life and Intervals
6 key facts
Piping Calculations (ASME B31.3)
7 key facts
Flange Ratings (ASME B16.5)
6 key facts
Damage Mechanisms and Inspection Practices
6 key facts
Repairs, Alterations and Rerating
5 key facts
Welding (ASME Section IX, B31.3 and API 577)
6 key facts
NDE and Pressure-Relieving Devices
6 key facts

Each branch is a topic in the official outline. Members see every key fact on the full mind map. Read the free study guide →

How to pass the API 570 exam

  • Corrosion rate, remaining life, piping classes and the Table 1 interval maximums can all be asked closed book. Know them without looking.
  • B16.5 questions are table lookups: material group, class and temperature give the rating. Practice reading the tables quickly before exam day.
  • In B31.3 thickness problems, check which allowance to add: pressure design thickness t, then corrosion and mechanical allowances for the required thickness.
  • Only the RP 571 mechanisms on the effectivity sheet are tested, and only Sections 5, 6.1 to 6.5 and 7 of RP 576.

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What's in the premium API 570 prep

Premium API 570 prep is studied one topic at a time. Each step starts with that topic's key notes and flashcard deck, then its own question sets of 25, so you master one topic before you move to the next. When every topic is strong, the 6 full mock exams show you're ready.

3,000practice questions, every answer explained
6full-length mock exams, 170 questions each, timed
800flashcards with spaced repetition, sorted by topic
60comprehensive key notes across 7 topics

Your step-by-step study path

  1. 1
    Corrosion Rates, Remaining Life and Intervals9 key notes, 115 flashcards, then 450 practice questions in 18 sets of 25
    Notes free with an account
  2. 2
    Piping Calculations (ASME B31.3)9 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25
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  3. 3
    Flange Ratings (ASME B16.5)9 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25
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  4. 4
    Damage Mechanisms and Inspection Practices9 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25
    Premium
  5. 5
    Repairs, Alterations and Rerating8 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25
    Premium
  6. 6
    Welding (ASME Section IX, B31.3 and API 577)8 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25
    Premium
  7. 7
    NDE and Pressure-Relieving Devices8 key notes, 110 flashcards, then 425 practice questions in 17 sets of 25
    Premium
  8. Final step: 6 full mock exams170 questions each, timed like test day. Pass them, then book your exam.
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Free with an account

Read the complete API 570 study notes for “Corrosion Rates, Remaining Life and Intervals”

Our first full set of comprehensive notes, about 15 minutes of reading: Corrosion rate and remaining life · Piping classes · Table 1 maximum intervals (no RBI) · Injection points and dead legs · MAWP of corroded piping, a worked exam example, the traps examiners use and a one-minute recap. Create a free account to read it and see how premium notes work before you decide.

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Study tools included

3,000 practice questions

3,000 exam-style questions per exam, organized topic by topic in sets of 25. Every answer explained, with the rule it comes from.

6 full mock exams

6 full-length timed mock exams per exam, with real question counts and time limits, so test day feels like practice day.

Exam Readiness Score

One 0 to 100 number that tells you when you're ready to book. Reach 80 and you're covered by our Pass Guarantee.

800 flashcards + spaced repetition

800 flashcards per exam, in a deck for each topic, that come back right before you'd forget them. Five minutes a day keeps every number fresh.

60 comprehensive key notes

60 key notes per exam, split across its topics and each explained in full: the concepts, worked exam examples, the traps examiners use and a quick recap. Your first set is free with an account.

Mind maps

See the whole exam on one screen: every topic and the facts under it.

Sample questions with answers

These are the questions in the free test above, with answers. Try the test first. You'll learn more by getting some wrong.

1. A Class 2 piping circuit measured 0.280 in. in 2018 and 0.240 in. in 2026 at the same CML. The required thickness is 0.160 in. What is the remaining life?
Answer: 16 years. Corrosion rate = (0.280 − 0.240) ÷ 8 years = 0.005 in./yr. Remaining life = (t actual − t required) ÷ corrosion rate = (0.240 − 0.160) ÷ 0.005 = 16 years (API 570, Section 7).
2. A Class 2 circuit has a calculated remaining life of 16 years. Without RBI, what is the maximum thickness-measurement interval under API 570?
Answer: 8 years. The interval is the lesser of one-half the remaining life (16 ÷ 2 = 8 years) or the Table 1 maximum for Class 2 (10 years), so 8 years. The Table 1 thickness maximums are 5 years for Class 1 and 10 years for Classes 2 and 3.
3. A process line carries a gaseous stream with more than 3% hydrogen sulfide by weight. Which piping class does API 570 normally assign?
Answer: Class 1. API 570 lists hydrogen sulfide (greater than 3 wt %) in a gaseous stream as a Class 1 service, with anhydrous hydrogen chloride, hydrofluoric acid, services that can rapidly vaporize or auto-refrigerate, and piping over or next to water and public throughways. Class 1 has the shortest maximum intervals.
4. Seamless ASTM A106 Grade B pipe has D = 6.625 in., a design pressure of 600 psig, S = 20,000 psi, E = 1.0, W = 1.0 and Y = 0.4. What is the pressure design thickness t under B31.3, 304.1.2?
Answer: 0.0982 in.. t = PD ÷ [2(SEW + PY)] = (600 × 6.625) ÷ [2 × (20,000 + 240)] = 3,975 ÷ 40,480 = 0.0982 in. Leaving out PY gives 0.0994 in.; forgetting the 2 gives 0.1964 in. The minimum required thickness adds corrosion and mechanical allowances to t.
5. A piping system has a design pressure of 300 psig, and the allowable stress at design temperature equals the stress at test temperature. What is the minimum hydrostatic leak test pressure under B31.3?
Answer: 450 psig. 345.4.2: the hydrostatic test pressure is at least 1.5 × design pressure = 450 psig, raised by the stress ratio when the design temperature is above the test temperature. 330 psig (1.1 × design) is the pneumatic test pressure from 345.5.4.
6. A pipe measures 0.320 in. The corrosion rate is 0.008 in./yr and the next inspection is in 5 years. What wall thickness does API 570 use to calculate the MAWP for continued service?
Answer: 0.240 in.. API 570 uses the actual thickness minus twice the estimated corrosion loss before the next inspection: 0.320 − 2 × (0.008 × 5) = 0.320 − 0.080 = 0.240 in.
7. What system hydrostatic test pressure does ASME B16.5 permit for a Class 150, Material Group 1.1 flanged joint?
Answer: 450 psig. B16.5 allows flanged joints a system hydrostatic test at 1.5 × the 100°F (38°C) rating, rounded up to the next 25 psi: 1.5 × 285 = 427.5, rounded up to 450 psig. Testing above that is the user's responsibility.
8. What is the pressure rating of an ASME B16.5 Class 300 flange in Material Group 1.1 (for example A105) at 400°F?
Answer: 635 psig. Table 2-1.1, Class 300: 740 psig up to 100°F, 680 at 200°F, 655 at 300°F, 635 at 400°F and 605 at 500°F. Ratings drop as temperature rises, so read the column for the design temperature.
9. Which location is most susceptible to vibration-induced fatigue cracking?
Answer: A small-bore socket-welded branch with an unsupported valve near a reciprocating compressor. RP 571 and RP 574 point to small-bore connections, socket welds and unsupported masses such as valves and instruments near pumps, compressors and control valves. Look for visible vibration, missing or loose supports and cracks at weld toes.
10. Under API 570, where does the upstream limit of an injection point circuit start?
Answer: The greater of 12 in. (300 mm) or three pipe diameters upstream of the injection point. The upstream limit is the greater of 12 in. or three pipe diameters. Downstream, the circuit ends at the second change in flow direction past the injection point, or 25 ft (7.6 m) beyond the first change in flow direction, whichever is less.
11. Under API 570, what is required before an alteration to a piping system starts?
Answer: Approval by a piping engineer, then authorization by the inspector. All repair and alteration work must be authorized by the inspector before it starts. For alterations, the inspector authorizes only after a piping engineer has approved the work. The inspector may give prior general authorization for limited or routine repairs.
12. A welder passes a performance test on pipe in the 6G position. Under ASME Section IX, which groove-weld positions does this qualify?
Answer: All positions. QW-461.9: a 6G pipe test qualifies groove welds in all positions on plate and pipe (within the diameter limits of QW-452.3), and fillet welds in all positions.
13. A WPS is supported by a PQR on a 1/2 in. (13 mm) groove-weld test coupon. Under QW-451.1, what base metal thickness range is qualified?
Answer: 3/16 in. to 1 in.. QW-451.1: for coupons over 3/8 in. and under 3/4 in. thick, the qualified base metal thickness is 3/16 in. (5 mm) minimum to 2T maximum. 2 × 1/2 in. = 1 in., so 3/16 in. to 1 in.
14. Under ASME Section V Article 2, where should the image quality indicator (IQI) be placed when the source side is accessible?
Answer: On the source side of the part. T-277.1: IQIs are placed on the source side of the part being examined. Only when the source side is inaccessible may they go on the film (detector) side, identified with a lead letter 'F'.
15. Why does API RP 576 recommend pop testing a pressure-relief valve in its as-received condition, before it is cleaned?
Answer: To find out whether it would have opened at its set pressure in service, which guides the inspection interval. The as-received test shows how the valve would have performed in service. A valve that sticks or pops high points to fouling or corrosion, and the interval should be shortened.

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Certification guide

How to become an API certified inspector (510, 570 or 653): API 510 (pressure vessels), API 570 (piping) and API 653 (aboveground storage tanks) are the main inspector certifications in refining and petrochemicals. Each is run by the [American Petroleum Institute's Individual Certification Programs](https://www.api.org/products-and-services/individual-certification-programs) and needs documented experience, an approved application and a pass in a 7.5-hour exam. Here's the path.

API 570 exam FAQ

How many questions are on the API 570 exam?

170 multiple-choice questions (140 scored, 30 unscored pretest items): 110 closed-book and 60 open-book, with a time limit of 7.5-hour exam day: short tutorial, 2.75 hours closed book, 45-minute lunch, 3.75 hours open book. Format: closed-book part, then an open-book part with the effectivity-sheet code sections as on-screen pdfs. no paper books or notes; on-screen calculator.

What is the passing score for API 570?

Passing scaled score is 400 on API's 200 to 500 scale. The number of correct answers needed isn't published and varies by form; practice to 75% or higher.

How much does the API 570 exam cost?

US$875 API member / US$1,125 non-member (2026 fee table); US$890 / US$1,140 (2027 fee table). Reschedule US$350, late application US$200. API publishes a fee table for each year, so confirm the current fee on API's Schedules & Fees page before you apply.

Which languages is the API 570 exam offered in?

English; Spanish, Chinese and Korean translations available on request.

Where do I take the API 570 exam?

Prometric test centers, in person only (no remote option for API 570).

Is this API 570 practice test free?

Yes. The 15-question practice test on this page is free, with an explanation for every answer and no signup. A free account also unlocks the complete study notes for the first topic. The full API 570 prep is Premium at $147 a month for this exam.

What's in the premium API 570 prep?

3,000 practice questions organized topic by topic (Corrosion Rates, Remaining Life and Intervals: 450; Piping Calculations (ASME B31.3): 425; Flange Ratings (ASME B16.5): 425; Damage Mechanisms and Inspection Practices: 425; Repairs, Alterations and Rerating: 425; Welding (ASME Section IX, B31.3 and API 577): 425; NDE and Pressure-Relieving Devices: 425), 6 full-length timed mock exams of 170 questions, 800 flashcards and 60 comprehensive key notes split across all 7 topics, plus a mistakes bank and the Readiness Score.

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Exam details are summarized from the official candidate information available in November 2026. API changes formats and fees, so confirm with American Petroleum Institute (API) Individual Certification Programs (ICP) before you book. APIInspectorExam is not affiliated with the American Petroleum Institute (API), ASME or Prometric.

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