Acoustical design can be one of the most complex facets of architecture and construction. Depending on the purpose of a building or room, primary acoustical requirements may include sound control between spaces, sound control within a space, or listening efficiency (auditory quality) in meeting rooms and auditoriums. Each space has its own technical challenges. At Knauf, we offer various materials and design details to accommodate unique needs.
Sound can be defined as vibrations that travel through air, water, or physical objects, and can be heard when they reach a person's ear. Meanwhile, noise can be disruptive. Although this is subjective and depends on each individual’s reaction, disruptive noise can result in physical discomfort or mental distress. For this reason, a building’s sound insulation requirements should consider both internal and external sound transmission. Considering these factors at the design stage is especially important as remedial measures afterwards can be expensive and inconvenient to apply.
Principles
Building acoustics is the science of controlling sound and noise in buildings. The term itself embraces sound insulation and sound absorption, which are two distinct functions not to be confused. This discipline focuses on the minimisation of sound transmission from one space to another and the control of sound levels and characteristics within a space.
There are two types of noise transfer through partitions: airborne transfer and structure borne transfer. Both may need to be considered in order to achieve the desired result.
Performance
Any wall or floor/ ceiling partition system that separates one sole-occupancy unit from another must comply with the acoustic provisions as set out in the Building Code of Australia (BCA). Walls or floor/ ceilings that separate one room from another within the dwelling fall outside the scope of the BCA. However, an owner may wish to create quiet zones within the home by selecting internal wall or ceiling systems that have improved acoustic isolation properties.
Airborne Noise
Airborne noise is generated in the air within a room and passes through the partition into another room.
Structure Borne Noise
When a building element is directly or indirectly impacted or vibrated, some of the energy passes through the partition and is reradiated as noise to the room on the other side. This is called structure borne noise or impact noise.
Impact Sound Isolation for Walls
The most common sources of structure borne noise through walls are:
- Cupboard doors fixed to party (inter-tenancy) walls being closed
- Kitchen appliances being used on benches touching walls
- Plumbing fittings, particularly taps, being connected to walls
- Light switches being turned on and off
- Dishwashers, washing machines, or clothes dryers touching party walls.
Acoustical Solutions
While the science behind sound is well understood, using the principles to create the desired acoustical quality within a building or room can be complex. One acoustical solution isn’t universally applicable to all designs. Each environment features unique parameters the architect and designer must consider when developing floor plans, selecting materials, and designing assemblies. Virtually every material, from furniture and wall and floor coverings to computer equipment, will affect sound to some degree. Designing wall partitions, ceiling systems, and floor/ceiling assemblies for the distinct qualities of a space will achieve the most effective sound control.