AIV / FIV Vibration Screening

Energy Institute AVIFF likelihood-of-failure screening — traffic-light verdict

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Engineering Tips

Screens process pipework for acoustically-induced (AIV) and flow-induced (FIV) vibration fatigue using the Energy Institute AVIFF likelihood-of-failure method. Set the source ΔP to 0 to screen FIV only.

Screening basis:

• FIV: ρ·v² kinetic energy

• AIV: PWL = 10·log₁₀[(ΔP/P1)^3.6·W²·(T/M)^1.2] + 126.1

• Verdict: worst of FIV / AIV → traffic light

Recommended values

ρ·v²: Use operating density and bulk velocity. Higher ρ·v² → higher FIV likelihood.
Source ΔP: Only relevant for AIV from valves / orifices — set 0 for pure FIV screening.
D/t: Large-bore thin-wall pipe (high D/t) is the most AIV-susceptible.

Limitations

Screening only: An amber/red result triggers a detailed AVIFF assessment, measurement or FEA — not a substitute for them.
Scope: Does not cover pulsation (API 618), mechanical excitation or slug/two-phase FIV. Thresholds & PWL constant confirm against the current EI edition.

About the standards

Energy Institute AVIFF: Avoidance of Vibration Induced Fatigue Failure in Process Pipework.
Carucci–Mueller (1982): AIV sound power level correlation.

AIV / FIV Vibration Screening

Input Parameters

FIV — Main-Line Flow

AIV — Pressure-Reduction Source

Downstream Pipe (D/t)