Noise > Building Acoustics > Sound Insulation
Sound Insulation is a measure of how good a building element is at reducing sound as it passes through that element. Materials that are good for thermal insulation are not good (on their own) for sound insulation -see the insulation/absorption section of this site.
In many countries the
sound insulation performance of building elements is specified by law.
In the UK the performance of floors and walls separating dwellings in
new build and conversions is set out in Approved Document E of
Building Regulations; this document has been revised; the
document itself can be read
The testing method was BS.2750 but is now ISO-140; however they are essentially similar, [pay attention now] for airborne sound tests (relevant to speech and television noise) -
The new Building Regulations require tests to be carried out using the above procedure, but the end results for airborne tests are subject to a spectrum adaptation term (Ctr) which is almost always negative. The spectrum adaptation term weights the results towards better low frequency performance, i.e. structures that are better at low frequencies, e.g. heavy masonry, tend to produce better results. The single figure rating is expressed as DnTw+Ctr.
For impact sound (footfalls) a specific design of machine taps or raps on the floor (the machine is unimaginatively known as a tapping or rapping machine). Measurements are only made in the receiver room but the procedure is very similar to above except for the need to set the machine up in a number of positions on each floor.
The procedures are "horribly" complex. If you need these tests, you need to have them made by a competent noise consultant [see directory].