Acoustic camera - making noise sources visible

The operation of industrial and commercial facilities with adjacent residential neighborhoods repeatedly leads to noise conflicts. One of the greatest challenges in the remediation of noisy facilities is the localization of the relevant noise sources. Above a certain size, there is a multitude of noise sources and it is often not clear which of the sources is responsible for the disturbing immissions in the neighborhood. Depending on the propagation situation, other sources may be dominant. With the use of the acoustic camera, the dominant sources can be made visible. Thanks to this additional information, G+P's experts can better understand the overall acoustic system and can optimally advise operators and enforcement authorities on remediation.

How the acoustic camera works

A digital camera images the sound-generating object. At the same time, a precisely calculated arrangement of microphones (array) registers the emitted sound waves. Specially developed software calculates a sound map from this and links it to the optical image of the sound source. The levels are entered in color-coded form. Loud areas are colored red, quiet areas blue. The relevant sources are thus clearly identifiable. The mapping is based on the sound pressure. G+P has been using a Norsonic 848 camera for several years. The camera can be used quickly and easily and is characterized by its high resolution.

Example Swissmill building in Zurich

For the handling of noise complaints, the Environmental and Health Service of the City of Zurich (UGZ) wanted to find out from which parts of the large production building the dominant noise sources originate. To answer this question, recordings were made with the acoustic camera at various positions.

The recordings showed a partly surprising picture. Depending on the recording position, the location of the dominant noise source changed. The main noise source assumed by the UGZ was not the dominant noise source in any of the locations investigated.

On the upper floors of the residential buildings opposite, noise immissions are dominated by equipment on the roof

On the lower floors and in the riparian area, the facilities on the roof of the building do not have a significant impact. Sources dominate in the southeastern part of the building:

Practical experience

The use of the acoustic camera in the processing of industrial noise projects has proven itself in many projects. Thanks to the recordings with the Acoustic Camera, hypotheses about the causes of noise problems can be confirmed or refuted, as in the example of Zurich.

For the planning of measures, a noise calculation model is often created so that the effects of the various measures can be examined. The recordings of the acoustic camera can provide a lot of information for the modeling or the plausibility check of the models. In many projects, we have been able to significantly improve the accuracy of our calculation model thanks to the results of the acoustic camera. The more accurate the model, the more meaningful the study of measures becomes.

Acoustic cameras provide images that are easy to understand, even for non-experts, and are excellent for communication. However, despite all the advantages of the technology, it must always be kept in mind that the acoustic camera is a highly advanced instrument for experts. In order to interpret the results of the acoustic camera correctly, a high level of acoustic expertise is required. G+P is happy to share its knowledge with you.