Sound insulation is the ability of a building structure to prevent sound from passing between two premises.
Two types of sound insulation will be discussed:
When airborne sound energy strikes a partitioning structure, some of the sound energy is reflected by the structure and some passes through. The structure thus reduces the sound energy that would otherwise be transmitted to adjacent spaces. The structure is said to have a sound reduction index R(dB), which indicates a particular air-borne sound insulation.
Good sound absorption in a room also reduces the sound transmission to the adjacent spaces, as well as the sound level generated in the receiving room.
The sound reduction of a structure depends on the frequency of the sound, the composition of the structure and how it is connected to surrounding structures.
The impact sound insulation is the reduction of defined footstep sound by a floor construction, expressed as the impact sound level Ln (dB) in the room below the floor.
For a sub-structure like a suspended ceiling the improvement is expressed as ΔLn (dB).
Suspended ceilings and sound insulation
A suspended ceiling system can improve sound insulation in several different ways, both horizontally and vertically.