API 570 Piping Inspection Code: Requirements [2026]

What is API 570, in plain terms?

API 570 is the American Petroleum Institute's Piping Inspection Code. It sets how owners keep in-service metallic (and fibre-reinforced plastic) process piping safe: how it is inspected, how corrosion rates and remaining life are worked out, how often each circuit is examined, and how repairs, alterations and re-ratings are controlled. It applies after construction. New piping is built to ASME B31.3 or another construction code.

The current edition is the fifth edition, published February 2024, issued alongside a revised API RP 574 on piping inspection practices. API's announcement lists added Inspection Supervisor roles, stronger requirements for pressure-relieving devices, and guidance on deferring inspection and repair recommendations among the changes. API 570 was first published in 1993. Free copies circulating online are usually old editions, and their clause numbers and figures should not be treated as current. Buy the code, in print or as an electronic copy, from API or an authorized distributor, and check API's errata and addenda. Source: API 570 and RP 574 announcement.

This section adds a plain-language map of the code: what is in and out of scope, who does what, how an API 570 programme actually runs, how it relates to B31.3 and RP 574, the regulatory overlay in the US and Canada, and the verified facts about the API 570 inspector certification. Requirements are paraphrased, not quoted; confirm them against your licensed copy.

What API 570 covers, what is optional, and what is out

API 570 is aimed at hydrocarbon and chemical process piping. Utility services such as water, steam and condensate are optional at the owner's discretion, and the code is not a substitute for construction requirements before the piping enters service.

Earlier editions (the 2016 fourth edition, for example) list the fluid services in scope. They include raw, intermediate and finished petroleum and chemical products; catalyst lines; hydrogen, natural gas, fuel gas and flare systems; sour water and hazardous waste streams above stated thresholds; hazardous chemicals; cryogenic fluids; and high-pressure gases. Services the owner/user may choose to include include water (including fire protection systems), steam and steam condensate, boiler feed water, and ASME B31.3 Category D fluid services. Check the scope clause of the fifth edition for the current list.

Three scope points cause the most confusion:

• There is no simple pressure threshold. API 570 scope is defined by fluid service and by the owner's programme, not by a "15 psi" or similar cut-off. Be wary of summaries that say otherwise.
• Buried process piping is covered. API 570 contains a section on inspecting buried piping, with methods such as above-grade surveillance of the route, close-interval potential surveys where cathodic protection is used, excavation and direct examination, and in-line or guided-wave techniques where practical. Cross-country pipelines regulated by PHMSA under 49 CFR 192 or 195 are a different regime.
• Construction stays with the construction code. API 570 is not to be used in place of the original construction requirements before the piping is placed in service. Where API 570 is more stringent than a regulation it governs; it must not be applied in conflict with regulation.

API 570 also expects the owner/user to have, or have access to, an authorized inspection agency, a repair organisation, and qualified piping engineers, inspectors and examiners. In the code, "inspector" means the authorized piping inspector, not every technician on site.

Who does what in an API 570 programme

The owner/user is responsible for the programme. The authorized piping inspector evaluates condition and accepts work. The piping engineer handles engineering judgements such as re-rating and complex repairs. NDE examiners collect the data. The repair organisation does the work.

The practical consequence: a contractor can supply every thickness reading on a unit without being the inspector of record. Your purchase order should say who the authorized piping inspector is.

How an API 570 programme actually works, step by step

An API 570 programme is a loop: classify the piping, break it into circuits, place condition monitoring locations (CMLs) where damage is expected, measure, calculate corrosion rates and remaining life, set the next inspection date within the code's limits, then repeat and adjust.

1. Classify. API 570 sorts piping into Classes 1 to 4 by the consequence of a leak. Class 1 is the highest-consequence service, Class 4 is essentially nonflammable and nontoxic, and each class has maximum intervals for thickness measurement and external visual inspection. Take the actual interval values from the current fifth edition, not from older copies. Owners may instead set intervals with RBI, an engineering programme the code permits and the owner commissions.
2. Circuitize. Group piping of similar material, service and expected damage into circuits, using damage mechanism guidance such as API RP 571.
3. Place CMLs. The code ties CML numbers and locations to damage mechanisms and consequence. Add more where corrosion is localised or variable, at injection points and deadlegs, and where corrosion under insulation (CUI) is likely. Use fewer on long, straight, low-consequence runs. Earlier editions also call for readings around the circumference of pipe and fittings, with attention to the inside and outside radius of elbows and tees.
4. Measure. UT thickness or profile radiography at CMLs, plus external visual inspection, CUI inspection, and special-emphasis inspections such as injection points, deadlegs, small-bore and auxiliary piping, and soil-to-air interfaces.
5. Calculate. Long-term and short-term corrosion rates from successive readings, remaining life from current thickness minus required thickness divided by the rate, and required thickness from the pressure design calculation of the construction code plus any structural minimum.
6. Set the next date. The thickness interval is limited by a fraction of remaining life as well as by the class maximum. The external visual interval follows the class.
7. Act and record. Repairs, re-ratings and deferrals follow the code's rules. The fifth edition adds guidance on deferring recommendations. Everything goes into the permanent record.

For more detail on CML placement see piping circuit and CML inspection. For triggers beyond thickness see what triggers an internal piping inspection.

API 570 vs ASME B31.3 vs API RP 574

ASME B31.3 builds the piping, API 570 is the in-service code with mandatory requirements, and API RP 574 is the recommended-practice companion that explains how to inspect piping components, valves and fittings.

In-service repairs follow the principles of B31.3 or the original construction code as far as practical, and the code also cautions that B31.3 construction radiography acceptance criteria may not be appropriate for judging in-service welds. See ASME B31.3 explained and the API 510 vs API 570 comparison.

NDE methods used in API 570 inspections

UT thickness at CMLs and profile radiography do most of the work. Corrosion mapping, guided wave screening and pulsed eddy current extend coverage, and PAUT, TOFD and wet fluorescent MT answer cracking questions.

• UT thickness: the core corrosion-rate tool. Data quality (temperature correction, coating, repeatable locations) matters as much as instrument choice.
• Profile radiography: wall loss and deposits on small-bore and insulated lines without removing insulation; the preferred approach for insulated small-bore piping in earlier editions.
• Corrosion mapping and PAUT: localised corrosion, erosion patterns and injection-point damage.
• Guided wave testing: screening long runs, road crossings and pipe racks; indications are then proved up with UT.
• CUI methods: visual with insulation removal, profile RT and pulsed eddy current screening. See CUI inspection.
• Crack detection: shear-wave UT, PAUT and TOFD for environmental cracking. API 570 identifies applications where UT shear-wave examiners should have passed a performance demonstration, such as the API QUTE family.

The regulatory overlay: OSHA PSM, states and Canada

In the US, OSHA PSM is the main legal driver. Piping in covered processes must be inspected to recognized and generally accepted good engineering practice (RAGAGEP), and most facilities cite API 570. In Canada, provincial regulators reference API 570 through CSA B51 and their own owner-user programmes.

Under 29 CFR 1910.119(j), piping systems including valves are covered equipment. Inspections must follow RAGAGEP, at frequencies consistent with good engineering practice, and each must be documented with date, inspector, equipment identifier, description and results. OSHA's RAGAGEP guidance treats a code's "shall" provisions as mandatory and expects documented justification for departures from "should" provisions. State boiler and pressure vessel laws generally focus on boilers and vessels rather than process piping; confirm locally. In Canada, Technical Safety BC lists API 570 among codes referenced through its adoption of CSA B51, Alberta applies API codes through ABSA's AB-506 owner-user requirements, and Ontario sets its own inspection rules through TSSA. Confirm with your provincial regulator.

API 570 certification: the verified facts

The API 570 Piping Inspector certification is issued by API ICP. You need education plus piping-related experience gained within the last 10 years with an authorized inspection agency, then a 170-question exam at a Prometric centre. The term is three years. These facts come from API's API 570 program page:

• Eligibility: BS or higher in engineering/technology (or 3+ years technical military service) plus 1 year supervising or performing API 570 inspection; 2-year degree or certificate plus 2 years; high school diploma plus 3 years; or no formal education plus 5 or more years. On the non-degree routes, at least 1 year must be in inspection supervision or performance. No NDT Level III certificate is required.
• Exam: 170 questions (140 scored), 110 closed-book and 60 open-book, about 7.5 hours with a lunch break, in person at Prometric centres only. "API 570 online" testing ended when remote proctoring was withdrawn for 510, 570 and 653 from the September 2024 window.
• Recertification every three years: at least 20% of working time on in-service piping inspection, 24 hours of continuing professional development, and an open-book web quiz every six years.

Atlantis does not provide API exam preparation. For the NDE side of a piping inspector's skill set, the complementary path is ASNT SNT-TC-1A method training; see ASNT certification.

How Atlantis supports API 570 programmes

Atlantis performs the NDE an API 570 programme runs on: CML thickness surveys, profile RT through licensed radiography crews where the work is, corrosion mapping, PAUT, TOFD, guided wave screening and CUI inspection. The work is done by ASNT-certified technicians under ASNT Level III oversight. Results go to your authorized piping inspector, who stays inspector of record and sets intervals and repair decisions. We do not perform RBI or fitness-for-service assessments. Request an API 570 NDE scope; we reply within one business day. Atlantis has supported 1,500+ inspection activities.

More API 570 questions

What is API 570 inspection?

An inspection carried out under the owner's API 570 programme. That covers external visual inspection, thickness measurement at CMLs, CUI inspection and special-emphasis checks such as injection points and deadlegs, with an authorized piping inspector evaluating the results and setting the next date.

Can I take the API 570 exam online?

No. Since the September 2024 window, API 570 is delivered in person at Prometric test centres only. Check API's program updates page for any change. Ask about ASNT UT training for the NDE side of piping work.

Where can I get the API 570 code as an ebook or PDF?

Buy it from API or an authorized distributor, in print or electronic form, and make sure it is the current fifth edition with any addenda. Unofficial PDFs online are usually outdated editions and are not authorised copies. Talk to us about piping NDE once your programme is set.