ABSTRACT
Direct sound transmission across a single building element occurs where the elementis excited by an airborne or a structure-borne sound source on one side, and radiatessound from the other side without any flanking transmission. This chapter looks at predicting and interpreting features that describe the airborne and impact sound insulation of various building elements. Splitting up a building into its component parts (e.g. floating floor, concrete base floor, ceiling finish, flanking walls, wall linings) is a convenient way to approach calculation of the sound insulation; it also suits the way that designers and manufacturers approach the design of a building. In many cases this approach is well-suited to prediction using Statistical Energy Analysis (SEA); hence this is discussed at the beginning of the chapter. For some types of building elements this approach allows insight into sound transmission mechanisms from which decisions can be made on ways to improve the sound insulation. However, it is not suited to all types. The inability of prediction models to deal with every single type of building element indicates why laboratory measurements are so important in providing information at the design stage. At the same time we find that prediction models illustrate the inherent limitations of many laboratory measurements; in some cases the most useful information lies somewhere between the two.
