What is FIV and AIV?
Flow Induced Vibration (FIV) and Acoustic Induced Vibration (AIV) are major concerns in piping systems. FIV occurs due to turbulent fluid flow, while AIV results from high-frequency pressure fluctuations near control valves, relief valves, and orifices. Both can lead to fatigue failure, structural damage, and operational risks if not properly analyzed.
What is FIV Analysis?
FIV analysis is a method to assess piping integrity by evaluating the effects of turbulent flow and vibratory stress. It helps identify resonance risks and prevents pipe fatigue failures using computational fluid dynamics (CFD), finite element analysis (FEA), and vibration screening techniques.
What is FIV in Engineering?
In engineering, Flow Induced Vibration (FIV) is the vibration of piping and structures caused by high-velocity fluid flow. It can lead to structural resonance, fatigue cracks, and mechanical failures in offshore platforms, petrochemical plants, and onshore processing facilities. Proper FIV screening and mitigation ensure safe and reliable operations.
Mitigating Vibration-Induced Fatigue in Industrial Piping
At iFluids Engineering, we provide industry-leading Acoustic Induced Vibration (AIV) and Flow Induced Vibration (FIV) screening and analysis services to ensure the mechanical integrity of critical piping systems. Our methodology adheres to internationally recognized engineering standards, including Energy Institute (EI) Guidelines, DEP standards, and CONCAWE 85/52 acoustic fatigue guidance. Our services help offshore platforms, FPSOs, petrochemical plants, and onshore processing stations identify and eliminate vibration-induced fatigue risks at both design and operational stages.
Our AIV & FIV Engineering Services
1. Flow Induced Vibration (FIV) Screening & Assessment
FIV results from turbulent flow conditions that generate oscillatory forces, which can lead to fatigue failure. Our approach includes:
- Preliminary and Secondary Screening: Using Energy Institute guidelines, we calculate the Likelihood of Failure (LOF) for each pipeline segment.
- ρv² Criteria Analysis: This critical parameter helps identify turbulence-induced energy risks in pipelines.
- Support Span & Stiffness Evaluation: Ensuring adequate support and stiffness to prevent resonance and excessive vibration.
- Mainline & Small Bore Connection (SBC) Risk Categorization: Identifying vulnerable small-bore branches and high-risk pipeline sections.
- Site Surveys & Construction Audits: Verifying field conditions, including improper bracing, fabrication defects, and misaligned supports.
LOF-Based Recommendations:
- LOF < 0.3: Safe under current conditions; routine monitoring recommended.
- 0.3 ≤ LOF < 0.5: Evaluate SBC integrity; minor modifications may be required.
- 0.5 ≤ LOF < 1.0: Requires mechanical modifications, such as increased stiffness or additional supports.
- LOF ≥ 1.0: Redesign necessary; high-risk zones demand reconfiguration and re-routing.
2. Acoustic Induced Vibration (AIV) Analysis
AIV occurs due to high-frequency pressure fluctuations, often near control valves, relief valves, or restriction orifices in gas systems. Our evaluation includes:
- Sound Power Level (PWL) Calculation: Using EI guidelines to assess acoustic energy levels.
- Initial Screening: Excluding low-risk pipelines to optimize resources.
- Detailed PWL Mapping: Identifying zones with high acoustic excitation.
- LOF Calculation: Evaluating pipe geometry, thickness, and exposure to high-frequency loads.
- D/T Ratio Analysis: Assessing structural vulnerability based on diameter-to-thickness ratios.
AIV Mitigation Strategies:
- Low-noise trims: Reduce acoustic energy during pressure reduction.
- Full-wrap reinforcement: Strengthening high-risk zones like tees and bends.
- Two-plane bracing for SBCs: Reducing vibration amplitude.
- Pipe schedule upgrades: Using thicker pipes to meet recommended D/T limits.
3. Combined AIV & FIV Risk Management & Design Validation
We offer holistic vibration risk management services, integrating:
- Cross-functional engineering review: Collaboration between stress, piping, and process teams.
- Finite Element Analysis (FEA): Advanced modeling for high-risk scenarios.
- Span Optimization & Stiffness Mapping: Ensuring optimal damping and flexibility balance.
- Project-Specific Compliance: Aligning recommendations with project piping philosophies.
4. Corrective Engineering & Field Mitigation Planning
For high-risk areas, we provide actionable engineering solutions:
- Structural reinforcements & rerouting: Strengthening joints with clamps, gussets, and wraparounds.
- SBC bracing retrofits: Designing field-installable supports.
- Vibration isolators & dampers: Absorbing vibration energy to prevent failure.
- Commissioning audits: Post-installation vibration monitoring and validation.
Industry Standards & References Followed
- Energy Institute Guidelines: Primary reference for vibration risk assessment.
- CONCAWE 85/52: Acoustic fatigue assessment framework.
- DEP SP-2373: Process piping design standard.
- EI TM-2.2 & TM-3: Screening tools for turbulence and SBC vibration analysis.
- Client-Specific Standards: Customizing solutions based on project specifications.
Why Choose iFluids Engineering?
✔ Specialized AIV/FIV Experts: Our team has extensive experience in mechanical, piping, and process design.
✔ Validated LOF Modelling Tools: We use verified Excel tools and code-based scripts following EI methodology.
✔ Design-Integrated Solutions: Our proactive approach eliminates costly rework.
✔ Post-Screening Support: We provide constructible solutions and on-site verification.
Get in Touch
Mitigate vibration-induced fatigue risks with expert AIV & FIV screening. Contact iFluids Engineering today to schedule a consultation for your project!