The nuisance of noise is regarded as a health and safety issue for persons living in dwellings and all occupants of a dwelling should be allowed to follow normal domestic activities, including sleep and rest, without threat to their health from noise.
Noise is transmitted in buildings by both airborne and impact sound sources and UK Building Regulations requires that both these noise types are controlled. Practical guidance to meet with Building Regulation requirements is given within Approved Document E.
Sound insulation, in general terms, is the prevention of airborne and impact sound being transmitted from one part of a building to another through separating floors, ceilings or walls.
Airborne sound sources produce noise by vibrating the surrounding air, for example speech, televisions and home entertainment systems. Airborne sound insulation is concerned with reducing this sound transmission through separating floors and walls.
Impact sound is caused by direct physical collision on part of a building, for example footsteps on a floor. Impact sound insulation is concerned with resisting this impact sound upon separating floors.
Flanking transmission occurs when sound is transmitted from one space to another indirectly, through adjoining parts of the structure, e.g. impact sound may be transmitted from one room to another through a timber floor, but also through the supporting wall.
Flanking transmission is always a potential problem within any structure, in particular, buildings being converted, and depending on the intensity of the acoustic energy received via flanking transmission paths, the effectiveness of sound insulation of separating partitions can be much lower than expected from their construction.
Careful consideration must be given to the effect of flanking transmission within any building and all potential flanking paths must be identified and eliminated prior to the installation of any system providing residential acoustics.