What Is API 570 Piping Inspection?
API 570 is the code an inspector reaches for when the asset is process piping rather than a tank or a vessel. This page explains what API 570 covers, how it fits alongside its sister codes, and where continuous monitoring data supplements it, for the mechanical-integrity or controls engineer who keeps seeing it referenced but has not read it. It is an overview aimed at practitioners, not a substitute for the code.
API 570 Piping Inspection in one line: API 570 is the inspection, rating, repair, and alteration code for in-service metallic process piping systems, published by the American Petroleum Institute. It governs piping already in operation - setting how it is inspected, how thickness data drives intervals, and how repairs and re-ratings are made - the way API 653 governs tanks and API 510 governs pressure vessels.
What API 570 Covers and Who Publishes It
API 570 is published by the American Petroleum Institute and applies to in-service piping systems in process facilities - refineries, chemical plants, and similar. It covers inspection, rating, repair, and alteration of piping that has already been built and put into service, deliberately leaving new construction to the design and fabrication codes.
It is one of API's three in-service mechanical-integrity codes, sitting beside API 653 for aboveground storage tanks and API 510 for pressure vessels. The three share a philosophy - qualified inspectors, thickness-driven intervals, engineering evaluation of findings - applied to different asset classes.
How It Fits the Mechanical Integrity Program
Within a facility's mechanical-integrity program, API 570 is the piping arm. It relies on thickness measurement locations, condition monitoring locations, and corrosion-rate tracking to decide when each piping circuit needs re-inspection and when it needs repair. The inspector performs; an engineer evaluates fitness-for-service and approves alterations.
The code leans heavily on corrosion understanding, including damage mechanisms specific to piping such as corrosion under insulation. Because piping runs long and connects everything, its inspection program is often the largest by data volume, which is why it increasingly blends with risk-based inspection to focus effort on the circuits most likely to fail.
Where Monitoring Data Fits
API 570 is a physical-inspection code, but the process data around the piping informs it. Operating pressure and temperature history, upset excursions, and flow conditions from SCADA help an engineer understand the damage mechanisms a circuit has been exposed to and where to look. Online corrosion probes and thickness sensors can supplement scheduled readings.
That said, monitoring supplements the program - it does not set the interval by itself. The thickness measurements and the engineer's evaluation remain the basis. Continuous data is best used to sharpen where and when inspectors focus, and to catch process excursions that would accelerate corrosion between inspections.
Common Misconceptions
A frequent misconception is that API 570 covers new piping design. It does not - design and initial fabrication are governed by the applicable construction code such as the process piping code. API 570 begins once the piping is in service.
Another is that piping can ride on the vessel or tank inspection schedule. Piping has its own damage mechanisms, its own thickness locations, and its own intervals under API 570. Folding it into the vessel program is how thinning elbows and dead legs go uninspected until they leak.
Frequently Asked Questions
What is the difference between API 570 and API 510?
API 570 covers in-service process piping systems; API 510 covers in-service pressure vessels. They share the same inspection philosophy - qualified inspectors, thickness-driven intervals, engineering evaluation - but apply it to different asset classes with different damage mechanisms.
Does API 570 apply to new piping?
No. API 570 is an in-service inspection code. New piping design and fabrication fall under the applicable construction code. API 570 governs the piping once it is operating - inspection, rating, repair, and alteration.
Can monitoring data replace API 570 inspections?
No. Process data and online corrosion monitoring supplement the program and help focus inspectors, but physical thickness measurement and engineering evaluation remain the basis for intervals and fitness-for-service decisions.
Sources and verification
This page references the standards, specifications, and official documentation published by the organizations below. Editions, product capabilities, and documentation change over time - confirm current requirements and specifications directly with the source.
- API 653, Tank Inspection, Repair, Alteration, and Reconstruction - American Petroleum Institute
Merobix is not affiliated with, endorsed by, or sponsored by these organizations; their names are used only to identify the standards and products discussed.
Automation services
Need help turning this into a working system?
Merobix integrates SCADA, programs Allen-Bradley and Siemens PLCs, and designs and fabricates industrial control panels.
Meeting requests are reviewed before confirmation.