Building acoustics

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Building acoustics is an area of building physics or acoustics that deals with the effects of structural conditions on the propagation of sound between the rooms of a building or between the interior of the room and the outside world.

Focus

Building acoustics is essentially concerned with the transmission of airborne and structure-borne noise from and through components. While the air-borne sound waves propagate in the room as pressure fluctuations, the structure-borne sound - usually in the form of bending waves - propagates along the building structure. Bending waves in turn cause airborne sound to be emitted and thus become audible. If airborne sound is generated in a room, its walls and ceilings are excited to vibrate, which in turn causes air particles in the neighboring room to vibrate, i.e. H. So stimulate airborne sound. This transmission process of airborne sound from one room to another is called airborne sound transmission. A distinction must be made between the structure-borne sound introduction. Is z. B. knocked on a wall with a hammer, this is also caused to vibrate, which again lead to corresponding vibrations of the air particles in the neighboring room, so to airborne noise. In this case, one speaks of structure-borne sound transmission to the neighboring room. In addition to the calculation of the sound insulation , metrological examinations are also a component.

In addition to the classic areas of airborne sound insulation ( sound insulation : sound reduction index ) and impact sound insulation ( impact sound insulation : standard impact sound level), the entire area of ​​structure-borne noise has played an important role.

The “more modern” areas of building acoustics include, above all, the generation and transmission of sound through sanitary installations and the precise pre-calculation of the expected sound insulation using analytical (mathematical-physical derivation) or numerical ( e.g. finite element ) methods. In the past, empirical methods were usually developed that came from metrological investigations.

For practical application and the design of components there are DIN 4109, DIN EN 12354, VDI guideline 4100 and numerous other regulations.

Building acoustics is closely related to room acoustics , as the sound pressure level in a room depends on the room acoustics (including reverberation time ).

Transmission mechanisms

All transmission mechanisms through components can be described in terms of excitability (input admittance or input impedance ), transmission behavior (transfer admittance or transfer impedance) and radiation behavior ( degree of radiation) of the sound of a structure (body). A distinction must be made between different types of waves: stretching waves (quasi-longitudinal waves, amplitude in the direction of propagation), bending waves ( transverse waves , amplitude orthogonal to the direction of propagation), torsion waves , ring waves, surface waves and ( Rayleigh waves ). The resonance frequencies of the mass-spring system represented by the component , the coincidence frequency (also the coincidence limit frequency) (bending wavelength corresponds to the expansion wavelength of the air), the mass per unit area (thickness × bulk density ) and the loss factor have a particular influence on the sound transmission through a component .

history

The pioneers of building acoustics in Germany included Karl Gösele , Lothar Cremer , Manfred Heckl , Peter Lutz and Wolfgang Fasold .
In other countries it was among others Leo Beranek (1914–2016, USA) and Franz Max Osswald (Switzerland). Osswald founded the acoustics laboratory at ETH Zurich in 1929 .

Web links

Footnotes

  1. ↑ FAZ.net November 2, 2019: Open your ears for the standard romper