API 576

Covers — inspection, testing, and maintenance practices for pressure-relief valves, pilot-operated PRVs, rupture disks, and weight-loaded pressure/vacuum vents in service, including interval setting, bench testing, and troubleshooting.

Does NOT cover (exclusions) — the following are governed elsewhere:

• Sizing/selection of relief devices → API 520; relief-system design/flare loads → API 521.
• Seat-tightness acceptance → API 527; orifice/dimensional data → API 526.
• Fixed-equipment inspection programs that own the intervals → API 510 / API 570.

API 576 is the maintenance/inspection layer; sizing and design live in API 520/521/526.

API 576 sets minimum recommended practices for relief-device inspection:

• Inspection Intervals — risk- and history-based intervals for removal, inspection, and testing.
• Bench Testing — verify set pressure, seat tightness, and operability before reinstallation.
• Condition & Troubleshooting — identify fouling, corrosion, chatter, and improper installation that impair relief function.
• Documentation — records of as-found/as-left set pressures and repairs.

API RP 576 is the recommended practice for inspecting and maintaining pressure-relieving devices in service. It complements the sizing/selection standard API 520 and the relief-system standard API 521 by keeping installed devices reliable: setting inspection intervals, bench-testing set pressure and tightness, and diagnosing failures.

Common problems it addresses — fouling, corrosion, chatter, and back-pressure effects — are the real-world reasons a correctly sized relief valve fails to protect equipment.

Engineering Note: A relief valve that passes bench set-pressure testing can still fail in service if the inlet/outlet piping causes chatter — inspect the installation, not just the valve.