API 581 / API 580

Risk-based inspection (RBI)

Probability of Failure × Consequence of Failure → next-inspection date and method. Higher risk = more frequent + more sensitive inspection.

Inputs

Asset tag

Asset type

Ageyr

Operating pressureMPa

Operating temperature°C

Wall thickness, currentmm

Minimum required thicknessmm

Corrosion ratemm/yr

Fluid class

Inventorykg

Hole size scenario

Inspection effectiveness (A best – E none)

Last inspection (YYYY-MM-DD)

Sour service?

Insulated?

API 581 — 5×5 risk matrix

PoF (rows, 1–5) × CoF (cols, A–E). Top-right = highest risk.

Enter inputs and click Compute RBI.