Presentation
Design assistance
Expertise
AIV
FIP / VIV
FIV / FIT
Pulsations
Survey

Piping vibration can lead to severe damage to main lines & auxiliary systems (small bore, thermowells etc.): vibration can induce cracks & leaks, leading to heavy maintenance and even installation shutdown. Proper understanding of the phenomena at stake is essential to prevent and mitigate these risks. Vibratec is a world-class expert that can help you keep your major piping vibration issues under control.

Risk assessment Troubleshooting Training

piping risk analysis
pipeline problem diagnosis
vibration reliability training

Vibration-induced fatigue failure in pipework is a major concern; the Energy Institute have published guidelines which propose methodologies to minimize these risks: “Guidelines for the avoidance of vibration induced fatigue failure in process pipework and Guidelines for the avoidance of vibration-induced fatigue failure in subsea systems.”

Part of these methodologies can be performed by non-specialists in vibration, but for more detailed assessment, specialist predictive techniques are needed. Vibratec are highly experienced in undertaking these techniques.

All pipework vibration excitation mechanisms can be predicted and controlled by VibraTec:

  • Flow-Induced Turbulence / Flow-Induced Vibration (FIT or FIV)
  • Acoustic-Induced Vibration (AIV)
  • Periodic Flow-Induced Excitation (FIP and VIV)
  • Pulsation due to reciprocating pumps and compressors
  • Mechanical excitation
  • Cavitation and flashing
  • Surge / momentum changes
  • Pulsation due to centrifugal equipment

Design assistance

FEA vibration equipment
piperack production design

As an experienced engineering consultancy supporting you throughout your projects, Vibratec will provide you:

  • Expertise: During early stages of the design process, Vibratec are your technical expert in project meetings to review procedures, data and drawings and provide all necessary preliminary recommendations regarding structural, acoustic and mechanical aspects.
  • Knowledge of the main Companies’ noise and vibration philosophies: The main points are to issue adapted specifications and to guide and control the necessary studies to be performed.
  • Interface between Engineering / Company and the machine Suppliers: Vibratec provide liaison with equipment suppliers to help ensure that machinery meets noise and vibration specifications or has any necessary noise / vibration control options applied.

Expertise

AIV studies evaluate the acoustic energy downstream from pressure-reducing valves, safety valves and other pressure-reducing devices. Piping design is compared to fatigue failure limits based on the calculated sound power level (SWL). If an AIV risk is highlighted, VibraTec are able to recommend practical modifications to the piping system, valves or other solutions to reduce dynamic stress levels.

Acoustic-Induced Vibration (AIV)

acoustic induced vibration
pipe tubing breakage

Flow-Induced Pulsation (FIP): Acoustic resonance of a gas in a dead leg side branch can be excited by the flow when instability is generated at the mouth of the branch connection. Vortex-Induced Vibration (VIV): Fluid flow over a body causes vortices to be shed at specific frequencies. In the case of thermowells or other probes inserted in the flow stream, care should be taken to ensure that the vortex shedding does not correlate with the natural frequency of the probe.

Periodic Flow-Induced Excitation (FIP and VIV)

vortex flow singularity

Turbulent flow within piping systems may lead to significant vibration levels. The objective of an FIV study is to identify the potential critical lines regarding FIV throughout the facilities and to recommend actions to reduce either the source of turbulence or the response of the critical lines. If simple mitigations are not feasible, detailed studies may be performed using more advanced techniques.

Flow-Induced Turbulence / Flow-Induced Vibration (FIT / FIV)

piping flow vibrations

In the same way as structures exhibit natural frequencies, the fluid within piping systems also exhibits natural acoustic frequencies that can amplify low levels of pressure pulsation, leading to excessive shaking forces in the piping system. Vibratec uses finite element analysis and pulsation analysis (as per API 618 and API 674) to predict and facilitate the minimization of these vibration levels.

Pulsation due to reciprocating pumps and compressors

API618 dynamic pressure
compressor mechanical pulsation

Piping survey activities can be split in three phases: The preparation phase comprises the selection of the lines which are the most likely to be subjected to vibration. This line selection is based on basic information :

  • Fluid and piping characteristics (flow-rate, density, diameter etc.)
  • Critical equipment (reciprocating pumps or compressors etc)
  • Reported problems.

Survey 1/3

engineers and industry close-ups
onsite vibration measurements

VibraTec experts perform a visual inspection of the selected lines, focusing on Small Bore Connections (SBC) and instrument tubing which are known to be among the main locations of fatigue failure. The main line support efficiency is also assessed. Surveys are undertaken in accordance with the Energy Institute document: “Guideline for the avoidance of vibration induced fatigue failure in process pipework”. During the survey, where a support, an SBC or instrument tubing appears critical, vibration measurements are undertaken.

Survey 2/3

SBC pipe inspection
vibration valve integrity
Industrial Worker

Vibration levels are measured and compared to vibration limits (VDI, EI Guidelines etc.) on the main lines and on the SBC. Levels are measured using a portable measurement device. Following the measurements, data analysis is used to determine the cause of the vibration. Remedial actions are often proposed on-site where they do not require further validation by computation. Typical recommendations that could be proposed on-site include, but are not limited to:

  • Adding new supports,
  • Modifying existing supports,
  • Controlling the unbalance and /or the setup of equipment,
  • Confirming the efficiency of pulsation bottles,
  • Improving design.

If necessary, in-depth diagnosis can be performed on identified critical items

Survey 3/3

piping vibration control
pipe vibration measurements

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