Sound Intensity

The measurement of sound intensity, rather than sound pressure, is a very useful measurement technique for a variety of situations. Sound intensity is a vector quantity (i.e. it has a direction) whereas sound pressure is a scalar quantity. This means that measurements of a specific noise source can be undertaken where there may be high contributions from extraneous noise sources, or the measurement is undertaken in a reverberant environment. Typical applications include the following:

  • The measurement of specific items of equipment (pumps etc.) and piping in industrial/petrochemical sites and offshore, where there may be noise from a number of separate noise sources and the item being tested is not the dominant noise source
  • Factory acceptance testing where the test is undertaken in a reverberant environment or there are extraneous noise sources (such as uninsulated compressor piping) which need to be eliminated
  • Identifying the noise emitting parts of a machine and quantifying each separate noise source to allow noise control measures to be applied

For transmission through facades, sound intensity can be used to identify any weak spots on the fa├žade and also to identify flanking transmission paths The measurement of sound intensity is carried out using a pair of phase-matched microphones separated by a defined distance. The measurement instrument analyses the signals from the two microphones to determine the sound pressure and velocity and multiplies these to give the sound intensity.

AECL owns sound intensity measurement equipment, which allows us to respond quickly to requests for surveys and shortens mobilisation times.