API 572

Key requirements (8)

• Inspection practices for pressure vessels (companion to API 510).
• External inspection minimum: every 5 years.
• Internal inspection minimum: every 10 years (or one-half remaining corrosion allowance life).
• On-stream UT inspection acceptable in lieu of internal in many cases.
• Damage mechanisms reference: API 571 (HIC, SOHIC, polythionic SCC, CUI, HTHA).
• TML (Thickness Measurement Location) selection on injection points, dead legs, mixing zones.
• RBI (API 580/581) may extend interval based on risk assessment.
• WFMT, PAUT, AUBT for high-priority weld inspection.