Acoustic monitoring can allow for different sounds in an environment to be measured and can aid in different stages of building renovation projects. One of the main objectives of BIM-SPEED project is to develop a tool for building indoor acoustic performance assessment. To achieve this, a tool was developed to be based on common standards which aims to support the decision-making process for renovation strategies. In order to successfully develop a tool, a measurement survey was performed at a Warmond demonstration site. This survey allowed all relevant data to be collected for an acoustic performance assessment before renovation, as well as for the calibration of BIM-based acoustic comfort models.

To determine the model calibration, the following three tests were performed:

1. Measurement of indoor and outdoor sound pressure levels (SPL)
2. Measurement of sound reduction Index (RW)
3. Localization of sound insulation leakages

For the SPL test, the sound pressure level was measured at varios locations both outside and inside the buildings at the Warmond demonstration site. This was to determine the exterior noise which would be utilized as input in both the acoustic model and the actual comfort level respectively. For instance, for one of the buildings, the outside sound pressure levels were measured by Near-field and Far-field microphones. The SPLs measured by the microphone would thus be used for the model calibration. 

The second test involved Measurement of sound reduction Index (RW), where a measurement microphone and a noise source (loudspeaker) were used for the buildings at the Warmond Demonstration site. For one particular building, results showed that the calculated sound reduction index was 37.50 dB, whereas the measured sound reduction index was 37.03 dB.

Finally, for the test of localizing sound insulation leakages, a Beamforming technique was performed. This consisted of a matrix of microphones which measured the spatial distribution of the acoustic pressure, as well as being used to map out the acoustic leakages on the building facades.

The beamforming output is a pressure contour map which, once superimposed to the room wall, enabled to locate any weak elements of the building envelope which had to be dealt with in the renovation design. As shown in Figure 3, an example of the beamforming measurement set-up and acoustic map is demonstrated. As indicated on the top right window corner, it was expected that there would be a sound insulation leakage due to the weak elements in the envelope insulation.

All in all, these tests demonstrated the success in collecting data calibration of BIM-based acoustic comfort models, and can indeed support the decision-making process for any future renovation strategies.