In July 2003, Approved Document E of the Building Regulations was amended. This meant that sound testing was now a mandatory requirement throughout all residential development, including conversions, refurbishments & extensions. The objective was to raise the standard of sound insulation in all dwellings.
Sound testing takes place at "pre-completion" stage. This means that the development needs to be almost complete with doors, windows and trickle vents fitted. During the sound tests, we require a quiet site so as not to affect the results.
There are two kinds of sound tests - airborne and impact. Airborne tests are carried out on walls and floors separating dwellings, impact tests are carried out on floors separating dwellings. Airborne tests are provided by using loudspeakers and a sound level meter. The loudspeakers produce noise in one room (source), the noise level is then measured in the adjacent rooms or separating partitions between dwellings (receiver). The difference between the noise levels in each room can then be calculated to give the sound reduction of the separating wall.
Impact tests are only performed on floors between adjoining dwellings. The test is performed using a "tapping" machine and a sound level meter. The machine 'taps' on the floor emulating the sound of people walking around or other 'impact' noises on the floor. Measurements are taken in the receiver room and a value for the impact sound can then be calculated.
LnT,w is the standardised weighted impact sound pressure level and is used to give the amount of noise present in the receiver room. A high LnT,w result represents poor performance between separating partitions.