Impact Sound

Impact noise is most often created by footfall, as well as from closing cupboards and scraping chairs, in adjacent apartments. By their nature, impact events transmit vibration energy straight into the structure of a building. These vibrations can then radiate as acoustic energy in adjacent spaces.

Impact noise is a common issue in apartment buildings and terraced houses. In the past, impact insulation performance has only been considered for vertically adjacent spaces (such as apartments that are vertically stacked, one on top of the other). This is reflected in the established theory for impact noise which has generally addressed only vertical transmission.

However, impact noise is transmitted in all directions once it enters the building structure, thus consideration of horizontal and diagonal impact noise can also be required in many situations. In particular, as footfall noise is efficiently radiated through concrete floor structures, horizontal impact noise radiation (that is, between horizontally adjacent spaces, on the same floor level) can often be a problem in large, concrete apartment buildings.

Note

INSUL does not calculate impact noise radiation in the horizontal or diagonal directions.

INSUL includes an impact insulation procedure which is based on Cremer's (2005) theory of point force excitation, and so can be used to evaluate vertical impact noise radiation for massive, rigid homogeneous constructions (typically concrete constructions).

INSUL also includes impact insulation procedures for lightweight floors also, based on theory described by Brunskog and Hammer (2003).

Caution

Users should be aware of the limitations. Like any prediction tool, it is not a substitute for test data.