API 570 Piping Inspector Certification 2026 — Exam, CUI, Sour Service, and Recertification Explained by an ASNT Level III
How much does API 570 certification cost?
API 570 application, exam and recertification fees are set by API Individual Certification Programs (API ICP) and vary by membership status — check the current fee schedule at api.org for exact figures. Atlantis NDT does not run API 570 exam preparation; our piping work is ASNT Level III consulting on NDE procedures and inspection-data review, scoped per programme — contact us for a tailored quote.
Reviewed by Atlantis NDT founder Anoop Rayavarapu, ASNT NDT Level III in five methods (UT, RT, MT, PT, VT), with 11+ years of international NDT field experience. This page summarises API 570 (5th edition, February 2024) and the API 570 Piping Inspector certification as published by API.
API 570 Eligibility and Exam Structure (api.org)
Eligibility combines education with piping-related experience within the last 10 years: a BS in engineering or technology plus 1 year; a 2-year degree plus 2 years; a high school diploma plus 3 years; or no formal education plus 5 or more years — each including at least 1 year in supervision or performance of inspection. No NDT certification is required. The exam has 170 questions (140 scored) over about 7.5 hours at Prometric test centers: 110 closed-book questions in 2.75 hours and 60 open-book questions in 3.75 hours, with references provided on screen. API reports a scaled score; remote proctoring ended in September 2024. API 570 windows run in February, June and October. The 2026 effectivity sheet lists API 570 5th edition, API RP 571 (15 listed mechanisms), RP 574, RP 576 (listed sections), RP 577, RP 578, ASME Section V and IX (listed parts), ASME B16.5, ASME B31.3 (2024) and ASME PCC-2 (listed articles); API 579-1 and API RP 580/581 are not on the list.
Inspection and Testing Practices — CMLs and UT Thickness
Condition monitoring locations (CMLs) are selected for the credible damage mechanisms per API 570 and API RP 574 — elbows, tees, reducers, injection points, deadlegs and other locations where damage is expected — and thickness is measured with UT calibrated per the owner's procedure (ASME Section V Article 23, SE-797, is the referenced practice). CUI-susceptible lines get targeted inspection at insulation damage, low points and penetrations, with screening methods such as profile radiography or pulsed eddy current followed by UT. Atlantis NDT's UT training is ASNT SNT-TC-1A-based — see Atlantis training.
API 570 classifies piping by consequence (Class 1 highest, Class 4 essentially non-hazardous). Recommended maximum thickness-measurement intervals are 5 years for Class 1 and 10 years for Classes 2 and 3 (3 years for injection points), always limited to one-half the remaining life; external visual maximums are 5, 5 and 10 years. CUI is most active in the temperature range where moisture is present under insulation (for carbon steel roughly 10°F to 350°F per API RP 571/583). Injection-point circuits run from the greater of 12 in. or three pipe diameters upstream to the lesser of the second change in flow direction or 25 ft beyond the first change downstream. The soil-to-air interface is generally considered to run from 12 in. below to 6 in. above grade. Deadlegs are inspected at locations where stagnant fluid collects. An RBI assessment per API RP 580 may set intervals instead of the table. Atlantis ERP tracks inspection records and due dates entered by the owner's team; interval determination stays with the authorized inspector — see Atlantis ERP.
Inspection Data Evaluation — Corrosion Rates and Remaining Life
Short-term corrosion rate = (t_previous − t_actual) / years between; long-term = (t_initial − t_actual) / years between; the inspector selects the rate that best reflects current conditions. Remaining life = (t_actual − t_required) / corrosion rate.
Pressure Tests, Repairs and Documentation
Pressure tests after repairs and alterations follow the construction code (for ASME B31.3, hydrostatic leak tests at 1.5 × design pressure adjusted for the temperature stress ratio, or pneumatic at 1.1 × with additional safeguards), with NDE alternatives only where API 570 permits. Repairs and alterations are authorized and accepted by the inspector. Records must allow corrosion rates, remaining life and next inspection dates to be traced. When damage exceeds API 570's acceptance rules, the owner may repair, rerate, replace or commission an engineering FFS assessment per API 579-1; Atlantis NDT does not perform FFS or RBI assessments.
Atlantis NDT Stack Integration — From API 570 Pass to Field Performance
Sour-Service Hardness Limits per NACE MR0175 / ISO 15156 — The Trap on Page-One Welds
NACE MR0175 / ISO 15156 sour-service hardness limits — 22 HRC max on carbon steel weld + HAZ, 28 HRC for some L80 grades — drive the rejection criterion on any weld facing wet H2S service. The common field trap: assuming PWHT alone delivers acceptable hardness. Reality — base-metal carbon equivalent, heat input, cooling rate and the PWHT cycle all interact, and a hard spot in the HAZ above the limit is a potential sulfide stress cracking initiation site (see the wet H2S damage section of API RP 571). Operator specifications for sour-service piping commonly require hardness surveys of welds and HAZ with portable hardness testers. Portable hardness testing is covered in Atlantis NDT's Level II method training under the SNT-TC-1A syllabus.
Frequently Asked Questions
Q1: What is the pass rate for API 570 candidates?
A: API's ICP status update (April 2025) showed per-window API 570 pass rates of roughly 45–70% between 2020 and early 2025.
Q2: Do I need API 510 first or can I jump straight to API 570?
A: No prerequisite — API 570 is independently eligible on its own education-and-experience rules. Many piping inspectors also hold API 510 or API 653; the order depends on your asset portfolio.
Q3: How does CUI inspection work on insulated lines without removing all insulation?
A: Targeted insulation removal at damaged jacketing, low points, supports and penetrations, plus screening with profile radiography or pulsed eddy current and UT confirmation; API RP 583 gives guidance on CUI programmes.
Q4: When does API 570 thickness data go to an API 579 FFS assessment?
A: When thickness or flaws fall outside API 570's own acceptance rules and the owner chooses an engineering fitness-for-service assessment rather than repair, rerate or replacement.
Q5: How often must I recertify?
A: Every 3 years: at least 20% of working time on inspection activities and 24 CPD hours, plus an online web quiz every 6 years. API sets the recertification fee.
Q6: Do operators require API 570 for piping inspection?
A: Many refiners and national oil companies specify API 570-certified inspectors for in-service piping, with ASNT-qualified UT/MT/PT technicians underneath; check the specific operator standard and contract.
Q7: Does Atlantis NDT run API 570 prep cohorts?
A: No. Atlantis NDT does not deliver API 570 exam preparation. Our API 570-related work is ASNT Level III consulting on NDE procedures and written practices for owner-operators — see API 570 piping inspection support.
Free Consultation + Tailored Quote
Atlantis NDT founder Anoop Rayavarapu — ASNT NDT Level III in UT, RT, MT, PT and VT — reviews NDE programmes for owner-operators. Free 30-minute consultation, tailored quote. Affordable, accessible, fully customizable. Contact Atlantis NDT, Training, Academy, ERP, Digital Twins, About.
API inspection guide library
Practical answers for owner-users and inspectors, from the NDE side of API 510, 570 and 653 work:
Most API 570 work runs on ultrasonic thickness and flaw data. Candidates can strengthen their UT skills and practise on the simulator; owner-operators can bring in Atlantis for the NDE and data review behind their API 570 programme, with the Authorized Inspector staying their own.
API 570 certifies the piping inspector: the person who sets inspection intervals for in-service process piping, evaluates thickness data against minimum required thickness, and approves repairs, alterations and reratings. The examination is an in-person Prometric sitting of about 7.5 hours, 110 closed-book and 60 open-book questions with scaled scoring, and has no certification prerequisite.
API 570 eligibility combines education with documented in-service piping experience: an engineering degree plus one year, a two-year technical degree plus two years, a high-school diploma plus three years, or no formal qualification plus five years, all in design, fabrication, repair, alteration or inspection of in-service piping. The open-book portion is examined against a named publication set — API 570 itself, ASME B31.3 as the construction code, ASME Section V and Section IX, and API RP 571, 574, 576, 577 and 578, plus ASME B16.5 and ASME PCC-2. API publishes a body of knowledge for each examination cycle naming the exact editions and addenda in force, and buying an out-of-date edition is the most expensive avoidable mistake in preparation because clause numbering moves between editions. Certification runs three years before recertification. The marks concentrate in minimum required thickness, corrosion rate, remaining life, and interval determination by piping class.
Source: API 570, Piping Inspection Code — Section 6 (inspection intervals) and Section 7 (inspection data evaluation), with ASME B31.3 as the construction code; eligibility and exam structure per the API ICP body of knowledge for the current cycle
Technically reviewed by Anoop Rayavarapu — ASNT NDT Level III (UT, RT, MT, PT, VT)
API 570 inspection intervals by piping class and circuit feature
Piping class or feature
Service it covers
Thickness measurement interval
External visual interval
What drives it shorter
Class 1
Highest consequence — flammable services that flash on release, toxic services, hydrogen and high H2S
5 years maximum
5 years maximum
Half the calculated remaining life whenever that is shorter
Class 2
General process services not classified as Class 1 or Class 3 — the bulk of a refinery
10 years maximum
5 years maximum
Half the calculated remaining life
Class 3
Low consequence — flammable but with low probability of significant harm on release
10 years maximum
10 years maximum
Half the calculated remaining life
Injection points
Any class, wherever a chemical, water wash or additive enters the stream
Treated as its own circuit, scanned upstream and downstream of the injection
With the parent circuit
Turbulence and mixing corrosion; API 570 recommends a 3-year maximum thickness interval
Soil-to-air interface
The buried-to-above-grade transition on any class
Inspected above and below grade at the interface
With the parent circuit
Localised external pitting concentrated at the moisture line
Dead legs and CUI-susceptible lines
Stagnant legs; insulated carbon steel sitting in the corrosion-under-insulation temperature window
Parent circuit interval plus targeted strip inspection under insulation
Follows the parent circuit
Water ingress under insulation, and microbiologically influenced corrosion in stagnant legs
The class intervals are ceilings, not schedules. API 570 requires the shorter of the class maximum and half the calculated remaining life, and the remaining-life calculation uses the higher of the short-term and long-term corrosion rate.
What is the API 570 body of knowledge for 2026?
API publishes a body of knowledge for each examination cycle listing every publication examined and the exact edition and addenda in force for that cycle. For API 570 it centres on API 570 itself, ASME B31.3, ASME Section V and Section IX, and API RP 571, 574, 576, 577 and 578, plus ASME B16.5 and ASME PCC-2. Verify the current cycle's document before buying anything, because clause numbering moves between editions.
What are the eligibility requirements for API 570 certification?
Education plus documented experience in the design, fabrication, repair, alteration or inspection of in-service piping, with the experience requirement falling as formal education rises: an engineering degree needs one year, a two-year technical degree two years, a high-school diploma three years, and no formal qualification five years. Experience must be attested by an employer, not self-declared, and weak documentation delays more applications than the exam fails.
How long is the API 570 exam and what is the pass mark?
About 7.5 hours at a Prometric test center: 110 closed-book questions in 2.75 hours and 60 open-book questions in 3.75 hours against the published reference set, which is provided on screen. API reports a scaled score rather than a percentage pass mark. The open-book half is a navigation test under time pressure, not a reading test — locating the governing clause fast is a drilled skill.
Do I need API 510 before taking API 570?
No. API 570 has no certification prerequisite and is independently eligible on its own education-and-experience criteria. Most working piping inspectors eventually stack API 570 with API 510 for pressure vessels and API 653 for storage tanks, because client specifications frequently name a combination rather than a single credential. The efficient order is whichever certification your current work is already generating documented experience toward.
How often do I have to recertify API 570?
Every three years: at least 20% of working time on inspection activities and 24 continuing professional development hours per cycle, plus an online web quiz every six years, per API ICP rules. Practically, a lapse costs more than the renewal: a candidate who misses the window re-sits in a later examination cycle, which means losing months of assignable scope, not weeks.
Can an ASNT Level III replace an API 570 inspector on a piping scope?
No, and the two are not interchangeable. An ASNT Level III holds technical authority over the NDT — writing and approving the UT procedure and qualifying the technicians who run it — which API certification does not confer. The inspection decision, meaning interval determination, fitness assessment and return-to-service sign-off, sits with the API-certified inspector under the governing code. Clean contracts name both roles separately.
Answering the questions candidates actually ask
API 570 — Piping Inspector covers in-service inspection, repair and alteration of process piping systems. The examination is built around API 570 itself, ASME B31.3 as the construction code, ASME Section V and Section IX, and API 574, 577 and 578 as supporting practices.
What decides the result
The marks concentrate in minimum required thickness, corrosion rate and remaining life, inspection intervals by piping class and service, CML placement and spacing, and injection-point and dead-leg requirements. The genuine discriminator between candidates who pass first time and those who do not is piping classification and the inspection intervals that follow from it, and locating the governing clause quickly in an open-book format — which is a practised skill rather than a knowledge one, and it is the reason drilling beats reading.
Related routes: API 510 for pressure vessels · API 653 for storage tanks. Holding more than one widens the scopes you can be assigned to, and client specifications frequently name a combination rather than a single credential. The efficient order is normally whichever certification your current work is already generating documented experience toward.
Frequently Asked Questions
Am I eligible for API 570 certification?
Eligibility is set by a combination of education and documented experience, and the required experience falls as the level of formal education rises — an engineering degree needs materially fewer documented years than entry from the shop floor. The experience has to be in work relevant to in-service inspection, repair and alteration of process piping systems, and it must be attested by an employer rather than self-declared. The most common reason an application is delayed is not the exam at all: it is experience documentation that does not stand up.
What is on the API 570 examination?
The examination is built around API 570 itself, ASME B31.3 as the construction code, ASME Section V and Section IX, and API 574, 577 and 578 as supporting practices. The parts candidates most often lose marks on are minimum required thickness, corrosion rate and remaining life, inspection intervals by piping class and service, CML placement and spacing, and injection-point and dead-leg requirements — and, in the open-book portion, simply locating the governing clause quickly enough. In practice the discriminator is piping classification and the inspection intervals that follow from it, and locating the governing clause quickly in an open-book format.
How should I prepare for API 570?
Time spent on calculations is the strongest single predictor of passing, ahead of total reading time. The pattern that works is: buy the current-edition references and tab them properly, read every referenced publication once, then drill the routine calculations until they are automatic, then sit timed full-length practice exams and remediate only the weak areas those expose. Candidates who read widely and calculate rarely tend to fail.
Which edition of the references applies?
The body of knowledge names the exact editions in force for each exam cycle, and it is locked well before the first window. Buying the wrong edition is the most expensive avoidable mistake in preparation, because the clause numbering moves. Check the current body of knowledge before purchasing anything, and see what changed in the current cycle.
How long does API 570 certification last, and what is recertification?
Certification runs for a defined term and then requires recertification, either by examination or by documented continuing work in the discipline depending on the scheme and how long you have held it. Recertification lapses are a routine audit finding and they are entirely avoidable — the renewal date belongs in the same system that blocks dispatch on any other expired qualification, not in a personal calendar.
Is API 570 worth holding alongside other certifications?
Usually yes, and the combinations matter more than the individual credentials. Holding more than one API inspector certification widens the scopes you can be assigned to and is frequently what a client specification asks for, while ASNT or ISO 9712 method certification underpins the NDT the inspection itself relies on. The right sequence is normally the certification your current work already generates experience toward.
Preparing with support
Structured preparation materially outperforms self-study on these examinations, mainly because they reward judgement and clause navigation rather than recall. Preparation runs year-round: self-paced online through Atlantis LMS, with an ASNT NDT Level III answering questions, and on-site for employer groups preparing together. Send a training enquiry; we reply within one business day.
One of our inspectors failed API 570 a second time — what are the retake rules and waiting period?
The retake rules, waiting periods and any limit on attempts are set by API and published in its ICP candidate documentation — they change periodically, so verify against the current publication rather than a remembered figure. Practically, a candidate may re-sit in a later examination window rather than immediately, which means a second failure usually costs a full cycle of availability, not a few weeks.
The more useful question is why. Two failures on API 570 almost always trace to one of three causes: treating it as a knowledge exam when it is a code-navigation exam under time pressure; strong field experience that answers "how we do it here" rather than "what the code says"; or weak calculation drill on remaining life, MAWP and interval determination. Each has a different remedy, and re-sitting without diagnosing which one applies produces a third failure. how structured preparation is built.
Do we accept an ASNT NDT Level III in lieu of API qualification for UT scopes on turnaround contracts?
For the examination itself, an ASNT Level III is the stronger qualification — that person can write and approve the UT procedure and qualify the technicians performing it, which API certification does not confer. For the inspection decision — interval determination, fitness assessment, return-to-service sign-off — an ASNT Level III is not a substitute, because those authorities sit with the API-certified inspector under the governing code.
The clean contract language separates the two roles rather than trading one for the other: NDT performed under an ASNT Level III's technical authority, results evaluated and signed by the API-certified inspector of record. Contracts that let one credential cover both create exactly the ambiguity an auditor pulls on.
Have a question shaped like these? Put it to an ASNT Level III — we answer the specific case, not the general one.