Piping Vibration Diagnosis

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Context & Issue

While rotating equipment design has been constantly improved over the years and vibrations are less often a major issue, piping vibrations are more frequently the weak point of Oil&Gas facilities.

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

Client Benefits

Intervention by experts with a global approach

Solutions can be proposed while the consultant is on-site

If necessary, solutions can be validated numerically by analytical or finite element analysis

Challenges for Vibratec

Risk assessment

How critical are the vibrations observed?

Root cause analysis

Vibrations can have many origins (process, mechanical, etc)!

Mitigation action

Add a support? Modify the process? There is no one-size-fits-all solution!

Risk assessment

Piping vibrations are very rarely monitored, so the initial alert usually comes from a human observation:

Vibrations visibly observed, indication of a low-frequency excitation,
Vibrations felt (hand / feet) when passing near a line,
Noise heard near a pipe or a device.

Once on-site, Vibratec’s consultant team’s first priority is to correlate these observations with measurements and compare them to criteria.

Vibration levels are measured on the main pipes, even if the main risk often comes from small bores and tubing. These levels may be compared to Energy Institute Guidelines, ISO or API criteria.

Root cause analysis

Piping vibration may be due to many causes:

Process (e.g high-velocity fluids leading to Flow-Induced Turbulences),
Organs (e.g valves, restricted orifices, thermowells which are potential sources of Flow-Induced Pulsations &/or Acoustic- Induced Vibrations),
Mechanical equipment, source of mechanical excitations, pulsations, etc.

It is therefore of utmost importance to distinguish the main excitations in each piping vibration issue. This identification is obtained by cross-analyzing collected information such as:

Frequency content,
Dependence on process parameters,
Correlation with rotating equipment cinematics.

Mitigation action

In many cases, the excitation source is not the only problem and vibrations are amplified by improper design of the line & connected structure. Typical defaults are:

Supporting structure not stiff enough,
Mechanical resonance with the pipes and structure’s natural frequencies,
Acoustic resonance in the line length,
Acoustic solution design (restricted orifice, anti-pulsation bottles, etc) inadapted to the system.

Piping vibration issues are therefore not trivial and involve various disciplines (piping, structure, process). The intervention of an expert with a global approach is necessary; thanks to its extensive experience and feedback from previous projects, Vibratec is the one you need. Mitigation may be proposed while the consultant is on-site, or, when required, solutions may be numerically validated with analytical or Finite Element Analysis.