API 570 Exam Study Guide (2026)
Everything the API 570 Piping Inspector Exam tests, topic by topic: what each section covers, the facts that come up most, and how to study it. Pair it with the free 15-question practice test.
The exam at a glance
| Questions | 170 multiple-choice questions (140 scored, 30 unscored pretest items): 110 closed-book and 60 open-book |
|---|---|
| Time | 7.5-hour exam day: short tutorial, 2.75 hours closed book, 45-minute lunch, 3.75 hours open book |
| Passing score | 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 |
| 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 |
| Certifying body | American Petroleum Institute (API) Individual Certification Programs (ICP) |
| Test provider | Prometric test centers, in person only (no remote option for API 570) |
Mind map: the whole exam on one screen
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.
1. Corrosion Rates, Remaining Life and Intervals
Corrosion rate and remaining life calculations, piping classes, the Table 1 maximum intervals for thickness measurement and external visual inspection, injection points, dead legs and soil-to-air interfaces. Formulas and interval rules can be asked closed book.
Key facts
- Long-term rate = (t initial − t actual) ÷ years; short-term rate = (t previous − t actual) ÷ years. Remaining life = (t actual − t required) ÷ corrosion rate.
- Thickness-measurement interval: the lesser of one-half the remaining life or the Table 1 maximum for the piping class.
- Table 1 maximums (no RBI): Class 1 thickness 5 years, external 5 years; Class 2 thickness 10, external 5; Class 3 thickness 10, external 10; injection points thickness 3 years.
- Class 1 examples: services that can rapidly vaporize or auto-refrigerate, H2S over 3 wt % in a gaseous stream, anhydrous HCl, hydrofluoric acid, piping over water or public throughways.
- Class 2 covers most process unit piping (for example hydrogen, fuel gas, natural gas, on-site strong acids and caustics); Class 3 covers flammable services that don't significantly vaporize, such as distillate and product lines to and from storage.
- Injection point circuit: from the greater of 12 in. or three pipe diameters upstream to the second change in flow direction downstream, or 25 ft past the first change, whichever is less.
Flashcards
Exam tip: Learn Table 1 as a grid (class against thickness and external). Questions often give a long remaining life to test whether you apply the class cap.
2. Piping Calculations (ASME B31.3)
Pressure design thickness of straight pipe, blanks, joint and casting quality factors, leak test pressures, impact test exemptions, preheat and heat treatment, thermal expansion and the MAWP of corroded pipe under API 570.
Key facts
- Pressure design thickness (304.1.2): t = PD ÷ [2(SEW + PY)]. Required thickness tm = t + c (corrosion, erosion, thread and mechanical allowances).
- Y = 0.4 for ferritic steels below 900°F (482°C); W = 1.0 below the weld strength reduction range.
- Weld joint quality factor Ej from Table A-1B (seamless 1.00, ERW 0.85, furnace butt weld 0.60); supplementary examination in Table 302.3.4 can raise it.
- Permanent blank thickness (304.5.3): tm = dg √(3P ÷ 16SEW) + c.
- Hydrostatic leak test (345.4.2): at least 1.5 × design pressure, times St ÷ S when the design temperature is above the test temperature. Pneumatic test (345.5.4): 1.1 × design pressure.
- API 570 MAWP of corroded pipe: use actual thickness minus twice the estimated corrosion loss before the next inspection.
- Thermal expansion comes from Table C-1 (total expansion per 100 ft between 70°F and the metal temperature).
Flashcards
Exam tip: Write the variables down with units before you calculate. Mixing D (outside diameter) with an inside diameter, or forgetting the 2 in the denominator, are the usual errors.
3. Flange Ratings (ASME B16.5)
Reading the B16.5 pressure-temperature ratings by material group, class and temperature; system hydrostatic test pressure for flanged joints; and minimum flange dimensions.
Key facts
- Ratings depend on three things: material group (Table 1-1, for example A105 is Group 1.1), pressure class (150 to 2500) and temperature.
- Group 1.1 Class 150: 285 psig up to 100°F, falling to 200 psig at 400°F. Class 300: 740 psig up to 100°F, 635 psig at 400°F.
- Ratings fall as temperature rises; interpolate between listed temperatures if the question asks.
- System hydrostatic test of flanged joints: 1.5 × the 100°F (38°C) rating, rounded up to the next 25 psi (1 bar).
- The 'most cost-effective flange' question means the lowest class whose rating meets the design pressure at the design temperature.
- Minimum flange dimensions (thickness, bolt circle, bolt count) come from the dimension tables for each class.
Flashcards
Exam tip: On exam day, find the material group first, then the class table, then the temperature row. Doing it in that order prevents reading the wrong table.
Test yourself on these topics
Take the free 15-question API 570 test, then save your results to unlock your Readiness Score and the mistakes bank.
4. Damage Mechanisms and Inspection Practices
The RP 571 mechanisms on the API 570 effectivity sheet (CUI, erosion, galvanic corrosion, MIC, soil corrosion, vibration fatigue, sour water and others) and the piping inspection practices in RP 574.
Key facts
- CUI affects carbon and low-alloy steels between 10°F and 350°F (−12°C and 175°C); look where insulation is damaged or water can enter.
- Vibration-induced fatigue: small-bore connections, socket welds and unsupported valves near pumps, compressors and control valves.
Flashcards
Exam tip: Tie each mechanism to a place on a real unit: where would you look for it? Exam scenarios describe a location and ask what damage to expect.
5. Repairs, Alterations and Rerating
API 570 rules for repair and alteration authorization and approval, temporary and permanent repairs, welding on in-service piping and rerating, plus the listed ASME PCC-2 articles.
Key facts
- All repair and alteration work must be authorized by the inspector before it starts; alterations need prior approval by a piping engineer.
- The inspector may give prior general authorization for limited or routine repairs.
Flashcards
Exam tip: As with API 510, keep the roles straight: the inspector authorizes and accepts; the piping engineer approves designs, alterations and reratings.
6. Welding (ASME Section IX, B31.3 and API 577)
WPS, PQR and WPQ review under ASME Section IX, the welding, preheat and heat treatment rules in B31.3 Chapter V, and welding processes and metallurgy from API RP 577.
Key facts
- Only SMAW, GTAW, GMAW or SAW appear in WPS/PQR review, one process and one filler metal per document, base metals limited to P-No. 1, 3, 4, 5 and 8.
- Groove coupons over 3/8 in. and under 3/4 in. qualify base metal from 3/16 in. to 2T (QW-451.1).
Flashcards
Exam tip: When a question asks whether a welder is qualified, check four things in order: process, position, thickness or diameter range, and continuity.
7. NDE and Pressure-Relieving Devices
ASME Section V Articles 1, 2, 6, 7, 9, 10 and 23 (SE-797) for piping NDE, plus the parts of API RP 576 on the effectivity sheet (causes of improper performance, inspection and testing, records) and RP 578 material verification.
Key facts
- Radiography: IQIs on the source side unless inaccessible; then on the film side with a lead letter 'F'.
- Article 9 covers visual examination: direct visual examination needs the eye within 24 in. (600 mm) of the surface at an angle not less than 30°.
Flashcards
Exam tip: RP 576 is limited to Sections 5, 6.1 to 6.5 and 7 for API 570. Spend your relief-device study time there, not on valve types.
How to pass
- 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.
Frequently asked questions
How long should I study for the API 570 exam?
Most working candidates need 4 to 8 weeks at 45 to 60 minutes a day. Book your exam once your Readiness Score has stayed at 80 or higher for about a week.
Can I take the API 570 exam online?
No. The API 510, 570 and 653 exams are taken in person at Prometric test centers only; API does not offer them by remote proctoring. 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. Check API's exam pages for the current rules.
What score do I need to pass the API 570 exam?
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. The exam has 170 multiple-choice questions (140 scored, 30 unscored pretest items): 110 closed-book and 60 open-book and a time limit of 7.5-hour exam day: short tutorial, 2.75 hours closed book, 45-minute lunch, 3.75 hours open book.
What are the most tested topics?
The outline covers corrosion rates, remaining life and intervals, piping calculations (asme b31.3), flange ratings (asme b16.5), damage mechanisms and inspection practices, repairs, alterations and rerating, welding (asme section ix, b31.3 and api 577), nde and pressure-relieving devices. Use the free practice test to see which ones you need most.
The premium API 570 study path
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.
Your step-by-step study path
- 1Corrosion Rates, Remaining Life and Intervals9 key notes, 115 flashcards, then 450 practice questions in 18 sets of 25Notes free with an account
- 2Piping Calculations (ASME B31.3)9 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25Premium
- 3Flange Ratings (ASME B16.5)9 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25Premium
- 4Damage Mechanisms and Inspection Practices9 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25Premium
- 5Repairs, Alterations and Rerating8 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25Premium
- 6Welding (ASME Section IX, B31.3 and API 577)8 key notes, 115 flashcards, then 425 practice questions in 17 sets of 25Premium
- 7NDE and Pressure-Relieving Devices8 key notes, 110 flashcards, then 425 practice questions in 17 sets of 25Premium
- Final step: 6 full mock exams170 questions each, timed like test day. Pass them, then book your exam.Premium
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Summarized from API's official candidate information and the rules cited, checked November 2026. Confirm current requirements with American Petroleum Institute (API) Individual Certification Programs (ICP).