The American Petroleum Institute (API) Individual Certification Programs (ICP) include three foundational in-service inspector certifications: API 510 (Pressure Vessels), API 570 (Piping), and API 653 (Storage Tanks). Of these, API 510 and API 570 are the most commonly held by refinery, petrochemical, and pipeline inspectors. They are similar in structure but cover different equipment with different code drivers, damage mechanisms, and inspection workflows. This 2026 guide compares API 510 and API 570 across the dimensions that matter to inspectors, employers, and project managers.
\n| Dimension | API 510 (Pressure Vessels) | API 570 (Piping) |
|---|---|---|
| Equipment scope | In-service pressure vessels (typically >15 psig design) | In-service metallic piping systems |
| Construction code reference | ASME BPVC VIII Div 1 / Div 2 / Div 3 | ASME B31.3 Process Piping (and B31.1 Power Piping) |
| Key inspection intervals | External: lesser of 5 yr or internal interval; internal/on-stream: lesser of 1/2 remaining life or 10 yr | Thickness: Class 1 5 yr, Class 2 10 yr, Class 3 10 yr (and max 1/2 remaining life); external: 5 / 5 / 10 yr |
| Risk-based extension | API 580 / 581 RBI; up to many years for low-PoF / low-CoF | API 580 / 581 RBI; similar extension philosophy |
| Repair / alteration code | API 510 Sections 7 & 8 | API 570 Section 8 & ASME B31.3 Chapter V |
| Primary damage mechanisms | Wall thinning, brittle fracture, fatigue, SCC, HTHA, creep | Same + CUI, MIC, injection-point corrosion, dead leg, NAC, sulfidation |
| Number of TMLs | Per-vessel, often 50 to 500 | Per-circuit, often thousands across a unit |
| NDT mix | Internal entry VT, UT thickness, PT/MT, RT/PAUT | External UT (lots of it), GWUT, PEC, RT, PAUT, PMI |
| Exam structure | 170 Q (110 closed-book + 60 open-book), about 7.5 h, Prometric | 170 Q (110 closed-book + 60 open-book), about 7.5 h, Prometric |
| Recertification cycle | Every 3 yr: 20% inspection work, 24 CPD hours; web quiz every 6 yr | Every 3 yr: 20% inspection work, 24 CPD hours; web quiz every 6 yr |
| Industry roles | Refinery / petrochemical / chemical plant inspector | Refinery / pipeline / process plant inspector |
| Body of knowledge size | ~300 pages of effective study material | ~350 pages (more code documents) |
API 510 covers in-service pressure vessels that are typically designed and built to ASME BPVC Section VIII (Divisions 1, 2, and 3). Scope includes shells, heads, nozzles, manways, internals, and pressure-relief devices on the vessel. Heat exchangers, columns, drums, separators, and reactors all fall under API 510 when in pressure-vessel service.
\nAPI 570 covers in-service metallic piping systems designed and built to ASME B31.3 Process Piping (or B31.1 Power Piping). Scope includes pipe, fittings, flanges, valves, and supports of process piping. Pipelines regulated by the US Department of Transportation are outside API 570; they follow 49 CFR 192/195 and pipeline standards such as API 1160.
\nVessels and piping have similar concepts but different practical implementations:
\nFor piping, inspection emphasizes thickness mapping at TMLs because internal entry is rarely possible. For vessels, internal entry is the gold standard but on-stream NDT increasingly substitutes.
\nBoth certifications require thorough knowledge of API 571 damage mechanisms. Many mechanisms apply to both, but emphasis differs:
\nAPI 510 (vessels):
\nAPI 570 (piping): All of the above PLUS:
\nPiping inspectors generally face a wider damage-mechanism diversity per shift than vessel inspectors.
\nAPI 510 vessel internal: Out-of-service shutdown, isolation, blinding, draining, gas freeing, confined-space entry, VT internal, UT thickness, PT/MT critical welds, RT/PAUT as needed.
\nAPI 510 on-stream: External NDT (UT thickness, PAUT corrosion mapping, profile RT, AUBT for HTHA). Reduces shutdown costs.
\nAPI 570 piping: Almost entirely external, on-stream. UT thickness at hundreds of TMLs per unit. Guided wave UT for screening long lengths. PEC for through-insulation CUI screening. Profile RT at elbows for erosion. PAUT or RT at welds when needed.
\nBoth exams follow the same API ICP structure (from api.org):
\nThe open-book part requires navigating the referenced codes quickly; practise with electronic copies.
\nAPI 510:
\nAPI 570:
\nEditions are listed on each program's Publications Effectivity Sheet. API RP 580 and API 579-1 are not on either BOK.
\nBoth exams test similar calculations with different code formulas:
\nAPI 510 inspectors typically work in:
\nAPI 570 inspectors typically work in:
\nMost senior inspectors hold both API 510 and API 570 (and often API 653 for tank-yard work). Stacking certifications dramatically increases earning potential and employability.
\nPay varies widely by region, employer, rotation and overtime. For US figures use attributed sources such as the Bureau of Labor Statistics or the ASNT salary survey; see our NDT inspector salary guide.
\nAPI ICP requires education plus equipment-related experience (verify current rules on api.org):
\nFor API 510 the experience must relate to pressure vessels, and for API 570 to piping (design, fabrication, repair, operation or inspection), with at least 1 year in supervision or performance of inspection on the non-degree routes. No ASNT or other NDT certification is required.
\nIf you can only take one initially, choose based on your current job:
\nIf you have time and budget, take API 510 and API 570 in the same year (typical 12 to 18-month plan).
\nAtlantis NDT does not run API 510 or API 570 exam-preparation or recertification courses, and does not provide RBI or fitness-for-service services. Our API-related work is ASNT NDT Level III consulting on NDT procedures and written practices, employer-based NDT training under ASNT SNT-TC-1A, and inspection software that holds CML, thickness and inspection-report data (Atlantis ERP and the Digital Twin platform). See the API 510 code guide and the API 570 code guide.
\nA: No — API typically schedules each exam on separate dates within the same cycle. You can register for both in one window.
\nA: Vessel nozzles and internal piping within the vessel boundary fall under API 510. External process piping connecting vessels falls under API 570.
\nA: API's own statistics show per-window pass rates in a similar band for both (roughly 45% to 72% between 2018 and early 2024, per the April 2024 ICP status update). API 570 has more code documents to navigate; API 510 has more calculation problems. Both require structured prep.
\nA: There is no official figure; many candidates plan several months of part-time study from the referenced codes. A prep course is optional.
\nA: Yes — heat exchangers under VIII Div 1 are vessels. Some specialized exchangers (e.g., TEMA) add operational considerations not in API 510 alone.
\nA: Yes — tanks are not vessels under API 510. API 653 is the tank-specific certification.
\nA: API certifies you as an inspector (code role); ASNT/PCN certify you in NDT methods (UT, RT, MT, PT). Many inspectors hold both. API 510/570/653 are role certifications; ASNT/PCN are method certifications.
\nA: Yes — Aramco, ADNOC, KOC, QatarEnergy, Sonatrach, OQ all explicitly recognize API 510/570/653 in their inspection contracts. Many tenders require dual API + ASNT/PCN.
\nA: All three are API ICP certifications. 510 = vessels; 570 = piping; 653 = tanks. Inspectors commonly stack all three.
\nA: No. API recertification is handled through API (20% inspection work time, 24 CPD hours, web quiz every 6 years). Atlantis NDT does not run API exam or recertification courses.
\n\nAtlantis NDT is an NDT technology and services company based in Houston, Texas, led by founder Anoop Rayavarapu (ASNT NDT Level III). We provide NDT training under ASNT SNT-TC-1A (Level I, II and III), ASNT Level III consulting on NDT procedures and written practices, and inspection software: the Atlantis ERP and the Digital Twin platform.
\nAtlantis NDT does not run API 510, 570 or 653, CWI, CSWIP or PCN exam-preparation courses; the guides on this site are free, independent study resources. Our ASNT-based training is delivered self-paced online or onsite at your facility.
\nCall us at +1 (281) 840-8969 or email sales@atlantisndt.com for a quote on corporate group NDT training, delivered self-paced online or on-site at your facility.
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