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Troubleshooting & noise mapping of a large gas compressor

In this application the sound field produced by a complex, large infrastructure in a highly reverberant environment with a high ambient noise level (115 dB SPL) is measured. The main part to be measured in this test are the large compressor and the associated process pipework. The main goal was to locate the dominant sound source which is causing abnormal noise levels (115 dB) in the plant. The Scan&Paint 2D system is used to perform the measurements.

Extracted from: Guiot, M., Fernandez Comesana, D., Korbasiewicz, M. and Carrillo Pousa, G., 2015. Turbo-compressor and piping noise assessment using particle velocity based sound emission methods. In INTER-NOISE and NOISE-CON Congress and Conference Proceedings (Vol. 250, No. 4, pp. 2944-2952). Institute of Noise Control Engineering.


  • Rank the sound sources on a large structure
  • Locate the dominant sound source causing abnormal noise levels
  • Locate this in an acoustic, challenging (reverberant) environment


Locate the dominant sound source on a large structure causing abnormal noise levels. Find measures after to reduce the current noise level of 115 dB.


The acoustic signals of the sound field are acquired by manually moving a P-U probe across a measurement plane whilst filming the event with a camera. At post-processing stage, the sensor position is extracted by applying automatic colour detection to each frame of the video. The results are finally combined with a background picture of the measured environment to obtain a visual representation which allows us to “see” the sound pressure, particle velocity or sound intensity spatial distribution.


Due to the size of the measured machinery, it is not possible to capture its whole surface with one camera view. Therefore, the compressor, and the associated process pipe work, will be measured separately. The average scanning time per camera position is only 10 minutes. The results of all three views will be displayed and compared to get detailed inside and ranking of sources. The unique and distinguish features of the microflown probe for particle velocity and sound intensity measurements enable finally a viable solution to measure in such challenging environment. Since most of the radiated acoustic energy is carried in the frequency range between 200 Hz and 20 kHz, the location of the noise sources causing the excessive noise should be revealed while studying this frequency range. The image on the left shows the result of the compressor and process pipes for this frequency range of 200Hz-20kHz. the machinery.

Successful troubleshooting and source localization

A detailed study of the noise distribution along the suction pipe highlights only one dominant source of noise in the middle section of the suction pipe. This part of the pipe contains a strainer which was designed to capture possible debris left inside of the pipe during its installation process. During normal operation of the compressor the strainer would resonate causing the entire pipe to vibrate and produce the excessive noise. After the strainer was removed the noise level in compressor hall was decreased to an acceptable level.