API 510 vs API 570 vs API 579 compares three American Petroleum Institute documents for pressure equipment. While API 510 is the inspection code for pressure vessels, API 570 is the matching code for metallic process piping. API 579-1/ASME FFS-1 is different, because it judges whether damaged equipment can stay in service.
API 510 sets the rules for inspecting, rating, repairing and altering pressure vessels while they operate. Likewise, API 570 covers in-service metallic piping. When an inspection finds a flaw, API 579-1/ASME FFS-1 offers a staged way to decide: run on, repair or rerate.
Which standard do you reach for when a wall reading comes back thin?
Picture a routine thickness survey on a process unit. An inspector logs a reading on a vessel shell, and then another on the line leaving its nozzle. Both are lower than last year’s figures. The planner wants to know when to look again. Meanwhile, the operations lead asks if the unit can keep running, and the engineer asks which document applies. Once you know the API 510 vs API 570 vs API 579 split, each question has a clear home.
What do API 510, API 570 and API 579 each cover?
API 510: pressure vessels
API 510 is the Pressure Vessel Inspection Code. API’s announcement of the 11th edition says the code governs vessels and their pressure-relieving devices while they operate. In practice, it covers inspection, rating, repair and alteration. The edition also adds a detailed section on analysing inspection results. Although the code targets hydrocarbon and petrochemical plants, the same announcement notes that other industries may apply it at their discretion.
API 570: process piping
API 570 covers the piping side. The fifth edition arrived in 2024, according to API’s announcement. Specifically, the code sets requirements for inspection, rating, repair and alteration of in-service metallic piping systems and their pressure relieving devices. Recommended Practice 574 sits beside it, because it gives practical guidance for inspecting pipes, valves and fittings.
API 579: flaw assessment
API 579-1/ASME FFS-1 works differently, because it is a joint API and ASME document. Its 2021 contents page opens with a general assessment procedure, and later parts cover brittle fracture, metal loss, pitting, hydrogen damage, weld misalignment and crack-like flaws.
How do the three compare at a glance?
Table 1. The three standards side by side
| Standard | Equipment in scope | Main job | Edition noted here |
|---|---|---|---|
| API 510 | Pressure vessels and the devices that protect them | While vessels operate, it sets inspection, rating, repair and alteration rules | 11th edition (API announcement) |
| API 570 | Metallic process piping and its pressure relieving devices | Once pipes are in service, it applies the same rules, with RP 574 as the practical companion | 5th edition (API, 2024) |
| API 579-1/ASME FFS-1 | Vessels, piping and tanks that contain flaws or damage | When a flaw falls outside code limits, it supplies the assessment procedures | 2021 edition (ASME contents page) |
How do the three standards work together in practice?
Think of API 510 and API 570 as the routine, and API 579 as the escalation path. Most days, the work stays inside the inspection codes. A finding that falls outside their limits then moves the conversation to an assessment.
- Name the item: a pressure vessel, a pipe run, or a storage tank. Because tanks have their own code, API 653, they sit outside this comparison.
- Plan and carry out the inspection under API 510 or API 570, then record the measurements.
- Set the readings against the code’s limits and its remaining-life calculations, then log the margin.
- If a flaw or damage sits outside those limits, begin an API 579 assessment at Level 1.
- Once the result is clear, write it down and pick an action: keep running, monitor, repair, rerate, or replace.
What does API 579 add that the inspection codes do not?
Both inspection codes recognise fitness-for-service and risk-based inspection as accepted ways to evaluate in-service damage. However, the detailed procedures live in API 579. In fact, its own scope statement says the methods supplement and augment API 510, API 570 and API 653.
The method works in three levels. Level 1 is a simplified screening, while Level 2 adds more detailed calculation. Then Level 3 brings in advanced analysis such as finite element modelling, as TÜV SÜD’s published overview describes.
However, a Level 1 miss is a question, not a verdict. An Inspenet engineering article lists four routes after one: repair, rerate, a Level 2 assessment, or a Level 3 assessment.
API 510 vs API 570 vs API 579: which standard applies to your equipment?
Match your situation in the left column to the starting point on the right, because each row gives its reason.
Table 2. Where to start for common situations
| Your situation | Start here, and why |
|---|---|
| When a vessel reaches its scheduled inspection | API 510, because the code sets the plan, the techniques and the records |
| If a process pipe run needs a thickness survey | API 570, since its inspection and rating rules live here, with RP 574 adding hands-on guidance |
| Once readings show more metal loss than expected | API 579, when its metal-loss parts can give staged acceptance checks |
| If a vessel will run at new conditions | API 510, because rerating falls inside its scope and API 579 can then support the calculation |
| When a line needs a weld repair or alteration | API 570, since repair and alteration of metallic piping are named in the code’s title |
| When an aboveground tank is due for review | API 653, because tanks have a separate in-service code |
How do the API 510 and API 570 certifications work?
API runs individual certification programmes for pressure vessel inspectors under API 510 and piping inspectors under API 570. According to API’s page for the piping credential, it lasts three years and carries ANSI accreditation. Although the exam has 170 questions, only 140 of them are scored. Eligibility rests on education and experience gained within the last ten years with an authorised inspection agency. API publishes a body of knowledge and a publications list for each exam year, so read the current ones before you study.
What should you check before settling API 510 vs API 570 vs API 579 for an asset?
Use this ten-point review on one asset. Because each point takes only a few minutes, you can finish in one sitting. Then the pattern shows whether the answer lies in an inspection code or in an assessment.
- Confirm the item type: vessel, pipe, or tank.
- Check which edition of the code your site has adopted before you read any limits.
- Pull the construction code and design data for the item.
- Gather the last two or three inspection records, especially thickness readings.
- Name the damage mechanism you suspect, for example general corrosion or cracking.
- Test the finding against the limits written in the inspection code, then note the margin.
- Match the flaw type to the relevant API 579 part.
- Decide who is qualified to run the assessment level you need, since higher levels call for trained engineers.
- List the follow-up options: monitor, repair, rerate, or replace.
- Set the next inspection date and log the basis for it.
Where do people mix up API 510 vs API 570 vs API 579?
- API 579 is an assessment method, not an inspection code. Instead, inspections happen under API 510 or API 570, and the results then feed the assessment.
- A Level 1 miss is not a repair order. It simply means the screening assumptions were too coarse for that flaw, so a Level 2 assessment may change the outcome.
- Process piping and regulated pipelines are different scopes, as an Inspenet comparison of API 570 and API 1169 points out, so confirm scope before you pick a document.
What else can you explore?
Reading the codes is one part of the job. Many people also build skills next door to their own role. Therefore, this map pairs four common starting roles with an EnergyEdge course that sits close by. Levels and lengths come from each course page, and the button opens the current schedule.
Which course sits closest to your role?
Table 3. Course finder
| Starting role | Why it helps | Course | Level and length | Link |
|---|---|---|---|---|
| Pressure vessel inspector or static equipment engineer | Once you see how a vessel is designed and built, inspection findings make more sense | ASME BPVC Section VIII, Division 1 – Pressure Vessels Design and Construction | Basic to Intermediate, about 3 days | See current dates |
| Piping or inspection engineer | Since you inspect the pipe, its thickness calculations and materials are worth knowing | ASME B31.3 Process Piping Systems in Industrial Plants | Intermediate, about 3 days | See current dates |
| Integrity, reliability or corrosion engineer | While you already track damage, risk-based inspection and fitness-for-service methods add depth | Asset Integrity and Life Extension | Basic to Intermediate, about 5 days | See current dates |
| Operations, maintenance or HSE lead | Because ageing equipment affects operations, the lifecycle and risk view helps | Asset Integrity and Life Extension | Basic to Intermediate, about 5 days | See current dates |
What are the next steps?
- Run the ten-point review on one vessel and one line this week.
- Ask your inspection lead which editions your site has adopted, because the answer decides which limits apply.
- Then pick one nearby course from the finder above and check its current schedule, or ask about a team session.
Once API 510 vs API 570 vs API 579 is clear, the next thin reading becomes a routine decision.
Sources
- API: API Standard 510, Pressure Vessel Inspection Code, 11th edition announcement
- API: API 570 Piping Inspector certification page
- ASME: API 579-1/ASME FFS-1 2021 table of contents
Course levels and lengths come from the linked EnergyEdge course pages. Details on editions, certification terms and assessment levels were checked against the sources above and API, ASME, TÜV SÜD and Inspenet pages.
FAQ
Start with the equipment: vessels fall under API 510 and metallic process piping under API 570. If an inspection finds a flaw outside the limits in either code, add an API 579 assessment to decide what happens next.
The equipment. While API 510 covers pressure vessels and their protective devices, API 570 covers in-service metallic piping and its pressure relieving devices. Both deal with inspection, rating, repair and alteration during service.
No. API 579-1/ASME FFS-1 is a separate joint API and ASME document, so it stands alone. Instead, it supplements API 510, API 570 and API 653. The inspection codes also point to it for flaw assessment.
Level 1 is a simplified screening. Then Level 2 is a more detailed calculation, and Level 3 is an advanced analysis, often with finite element methods. Because Level 1 is deliberately conservative, an item that misses it may still pass at a higher level.
Escalate when a flaw or damage falls outside the limits in the inspection code. The team then needs to know whether the item can keep running, needs repair, or needs a rerate. Because the higher levels are complex, an engineer with the right training usually leads them.
Both are valid for a three-year term and are ANSI accredited, according to API’s certification pages. However, each has its own exam, body of knowledge and eligibility rules.
API 653 is the in-service code for tanks. Meanwhile, API 579 also lists storage tanks among the equipment it can assess.
