Pipework Vibration Assessment
Pipework vibration assessments are essential as all piping systems, small-bore connections (SBC), static equipment and structures are subject to vibration and fatigue failure risks.
Fatigue failures can occur during both normal and transient operating conditions.
To mitigate this integrity risk, a piping vibration assessment is conducted during the design phase. High-risk locations are also tested during the operations phase. This piping vibration analysis (assessment) is based on the Energy Institute (EI) AVIFF Guidelines and other applicable methodologies and makes up an important part of an Asset Integrity Management (AIM) system.
The Energy Institute AVIFF Guideline is the recommended approach to identify and resolve piping vibration risks. AVT Reliability BV (formerly Van Geffen Reliability) has extensive expertise in pipe stress analysis, dynamic vibration analysis, transient flow, and other related design studies. Our unique approach is based on decades of actual field experience (troubleshooting) to solve piping vibration problems – a unique advantage in the design industry.
Our Solution
AVT Reliability has more then 50 years of combined experience and skills in piping vibration, including the assessment of large-scale piping projects. Our experts specialise in managing the risk of fatigue failures throughout the entire asset life cycle through services that include:
- Piping vibration and fatigue assessments for all production systems including fatigue risks on vessels, valves, heat exchangers, instrumentation, thermowells and flow meters
- Quantification of system response to various forms of excitation, including:
- Flow-induced vibration (FIV)
- Turbulent flow (FIT)
- Transients (hydraulic, gas, water hammer)
- Flow-induced pulsation (FIP, FLIP)
- Acoustic-induced vibration (AIV)
- Multiphase and slug flow
- On-site investigation, monitoring and troubleshooting of piping, static equipment and structural vibration issues
- Advanced engineering (FEA )
- Pipe stress (piping flexibility) and thermal analysis
- Anti-vibration products – Easy-Brace, Dynamic Vibration Absorber (DVA), Visco-Elastic Dampers
Offering
In general, there are two main factors that affect pipework vibrations:
- the strength of the excitation
- the flexibility of the piping system
The excitation mechanisms that cause vibration originate from three main sources:
- Acoustic/pulsation – time-varying changes in fluid pressure
- Momentum – time-varying changes in fluid density and velocity
- Machinery – unbalanced forces from operating machinery
There are always several possible solutions to eliminate the problem:
- Reduce the level of excitation to which the piping system is exposed
- Isolate the asset from the construction
- Support the piping system so it can withstand the applied dynamic forces
- Install anti-vibration products
Preliminary Measurements
In order to arrive at a correct solution, insight must first be obtained into the source of the vibration, the main excitation frequency, amplitude levels, force/impact, dynamic response, etc. Therefore, studies almost always start with on-site survey and dynamic (vibrations, pressure, temperature, strain gauge etc.). or static measurements.
Additional measurements
Depending on the situation and the problem, additional measurements such as excitation measurements (to determine local natural frequencies/sensitivities), ODS/Modal analysis and/or motion amplification surveys can be performed as well.
Solutions & Actions
Based on this data, whether or not in combination with an FEA study, the most optimal solution can then be proposed. To test a solution, temporary modifications are made in certain situations to demonstrate whether a solution is sufficiently effective.
