Each of the houses had its main bathroom on the upper floor and a kitchen and smaller bathroom on the lower floor. However, for sound-pressure measurements, absorptive panels were placed in the rooms to bring acoustic absorption into the range expected with normal furnishings. All doors were closed during sound tests. The acoustics tests were planned to provide data for comparing laboratory and field results. As well, researchers assessed the relationship between the sound power and the resulting sound-pressure levels observed in the rooms.
Sound pressure accounts for the intensity of the noise when the source is installed in a room.
Sound pressure depends not just on the source, but also on the listener's location and on the characteristics of the room. For instance, the larger the room and the more absorptive its surfaces and furnishings, the lower the resulting sound-pressure level. It is the sound-pressure level that determines user annoyance. The IRC study revealed that sound-pressure levels can be predicted quite well from the CSA standard laboratory tests. The range hoods gave slightly higher sound-power levels in the field measurements, but the bathroom exhaust fans had lower sound power in the field.