Elements of an API 570 Piping Inspection Program

Back to Blog

Circuits, Classes, and Roles

The first element is dividing the plant's piping into circuits - groups of piping with common service and corrosion behavior that can be inspected and trended as a unit - and classifying each by consequence. Class then drives attention, as covered under API 570 piping classes. Without sensible circuits, thickness data has nothing coherent to attach to.

Roles are the second element. A certified piping inspector performs and documents inspections; a piping engineer evaluates fitness-for-service and approves alterations and re-ratings. Keeping evaluation independent of the fieldwork is what prevents a program from rubber-stamping its own inspections.

Data, History, and Intervals

The data element is thickness and condition-monitoring readings taken at fixed locations, retained as a history so a corrosion rate can be trended. This history is the asset - a single reading tells you thickness today; a trend tells you remaining life. Damage mechanisms specific to piping, including corrosion under insulation and injection-point erosion, dictate where those locations go.

From the trend, the program computes intervals capped by not-to-exceed ceilings. Larger programs allocate inspection effort with risk-based inspection so the highest-risk circuits get the most attention. The program element is ensuring the interval calculation is done, documented, and revised as corrosion rates change - not just that inspections happen.

The Path From Finding to Decision

The final element is what happens when an inspection finds a problem. The program needs a defined route from a thinning circuit to a decision: monitor more closely, repair, alter, re-rate to a lower pressure, or retire. Each of those requires engineering evaluation and its own record. Process history from SCADA - pressure and temperature excursions - supports that evaluation by showing what the circuit has endured.

A program that inspects diligently but has no clear finding-to-decision path leaves the most consequential step undocumented. Auditors and incident investigators look precisely at whether findings were acted on, so closing that loop with records is as important as the inspections themselves.

Common Misconceptions

One misconception is that an inspection contract is a program. Contractors supply readings; the operator owns the circuits, the classification, the history, the interval logic, and the decisions. Those elements do not come in a contractor's report by default.

Another is that thickness readings alone constitute integrity. Readings without a trend, a rate, and a decision path are just numbers. The program's value is turning readings into defensible remaining-life decisions and a documented response to findings.

Frequently Asked Questions