Sound insulation refers to measures that reduce sound transmission from a sound source to a receiver. Appropriate measures (e.g. elastic surfaces, mass, separation of components) should primarily avoid or reduce the transmission of sound .
The term noise is not synonymous with the term sound. Sound is a measurable quantity. It is only through non-measurable individual or socio-cultural aspects that sound becomes disruptive sound, noise.
Sound can have various undesirable effects on living things. In humans, loud sound waves can lead to inner ear hearing loss (through damage to the organ of Corti ) and to balance disorders such as dizziness . However, indirect health damage caused by noise and noise, such as sleep disorders, is more common .
Sound spreads in mechanical vibrations and pressure waves. The sound vibrations audible to humans are in the frequency range from 16 to 20,000 Hz . The frequency range from 200 to 5,000 Hz is of particular importance for noise protection, as this range is particularly clearly perceived by the human ear. Sound pressure is perceived from a hearing threshold of 10 dB (A) and perceived as pain from a threshold of 100 dB (B). If the transmitter and receiver are in the same room, the sound intensity is reduced through sound absorption through attenuation . In addition to the air available in the room, the properties of the floor covering and furnishings play an important role. Structural sound insulation is possible if the transmitter and receiver are spatially separated.
Interfering sound is differentiated into airborne sound and structure-borne sound. With structure-borne noise, a solid (e.g. a wall) is excited directly. If a solid (e.g. a room ceiling) is stimulated by walking, it is called impact sound. The sound propagates in the air as a longitudinal wave at a speed of 340 m / s. In solids, sound propagates as a flexural wave depending on the density , layer thickness and frequency . The cut-off frequency of a solid is the frequency at which the propagation speed of the flexural wave in the solid is 340 m / s and the transition from airborne and structure-borne noise is particularly low-loss.
A further subdivision of the noise protection can be made by distinguishing between structural noise protection and subsequent noise protection. Structural noise protection is usually installed on the basis of simulations and empirical values during the planning and construction phase and can only be adapted with great effort after the building has been completed. Structural noise protection is the only way to prevent structure-borne noise from being transmitted between different rooms and / or floors. Subsequent noise protection, on the other hand, can be adapted exactly to the requirements of the respective room and is therefore very flexible. It is primarily used to guarantee sound insulation in cases where the sound source and receiver are in the same room.
For better sound absorption is recommended to make walls of enclosed spaces asymmetrically to furnish enclosed spaces sound-absorbing and sound bridges to avoid. The building geometry should be adapted to the sound insulation outside and inside. Sound absorption can be achieved both through sound absorption and sound insulation .
The room acoustics can be improved by optimizing the sound reflection of the room - e.g. B. by striving for a reverberation time that is optimal for the ear within a room for desired sound events or by adapting the sound generation to the reverberation time of the room. For example, in a church with a very long reverberation time (Cologne Cathedral with 13 seconds) one has to speak very slowly during the sermon in order to be understood.
Interfering noise from devices and machines, in particular, can be reduced by shielding. This is done, for example, by elastic decoupling from the surrounding structure and by housing , for example in the form of a soundproof cabin . Noise emissions from computers can be reduced by dispensing with a fan and by replacing the rotating hard drive with silent flash memory ( solid-state drive , SSD).
Another possibility is the use of anti-noise .
In addition to the legal regulations on noise protection, there are technical guidelines that claim to represent the generally recognized rules of technology. For structural noise protection in Germany this includes:
- DIN 4109 (sound insulation in building construction) and the examples and calculation methods regulated in supplement 1 (supplement 1 is omitted in the new DIN 4109 from March 2017) as well as the recommendation in supplement 2 for sound insulation in one's own area and increased sound insulation
- VDI guideline 4100
The DIN standard 4109 describes the minimum requirements for sound insulation. In its supplement 2, recommendations for increased noise protection are given. The VDI guideline shows three levels of noise protection for living spaces.
The DEGA recommendation 103 describes requirements for sound insulation for residential units regardless of the nature of the building. This enables a direct comparison. The DEGA recommendation shows 7 noise protection classes for residential units. A component of the DEGA recommendation is a noise protection pass , which, comparable to the energy saving pass, shows color-coded sound protection classes in a simple way.
Sound insulation classes make agreements on sound insulation in old and new buildings possible.
VDI guideline 4100
The VDI guideline 4100 provides different requirements for multi-family houses (or apartments) as well as single-family houses (also semi-detached and terraced houses), which differ in three classes. In addition, noise protection within apartments is divided into two classes. The sound insulation level I corresponds to the parameters of DIN 4109, while the VDI guideline uses improved parameters. In terms of sound insulation, higher dB are better (for airborne sound), and lower dB are better for reverberation (for impact sound). The maximum level is generally 10 dB above the specified values and relates to individual louder actions (opening and closing, switching on systems). The following parameters result.
Protection against airborne sound transmission in accordance with DIN 4109 with R ′ w ≥ 53 dB horizontally (vertically and 2-storey more). With sound insulation level II then with R ′ w ≥ 56 dB horizontal. With noise protection level III then with R ′ w ≥ 59 dB.
Protection against impact sound transmission in accordance with DIN 4109 with L ′ n, w ≤ 53 dB on apartment ceilings. At sound insulation level II then with L ′ n, w ≤ 46 dB. At sound insulation level III then with L ′ n, w ≤ 39 dB.
Protection against building services systems in accordance with DIN 4109 with L ′ AF, max ≤ 30 dB (A) on apartment ceilings. For sound insulation level II continue with L ′ AF, max ≤ 30 dB (A). At sound insulation level III then with L ′ AF, max ≤ 25 dB (A).
Protection against business in the building according to DIN 4109 with L ′ AF, max ≤ 35 dB (A) during the day and L ′ AF, max ≤ 25 dB (A) at night. With sound insulation level II for individual noises a maximum of 10 dB higher. With noise protection level III, commercial use in the building is regularly excluded.
Protection against external noise according to DIN 4109, the required sound insulation is determined according to the noise level range . In the case of noise protection level II, the value is accepted. At sound insulation level III, it is set 5 dB better.
In VDI 4100, Table 1, examples from acoustic consulting practice, i.e. subjective impressions, are listed that are easier for the layperson to grasp, e.g. B. "Loud language: SST I: understandable, SST II: generally understandable and SST III: generally not understandable".
Of course, there may be different personal judgments; the objective dB values in Table 2 for air and footfall sound insulation are decisive for a corresponding proof.
In 2007, the Federal Court of Justice ruled in a landmark ruling for semi-detached houses that the noise protection levels II and III of VDI guideline 4100 or the increased noise protection according to Supplement 2 of DIN 4109 are generally recognized rules of technology, but not level I or DIN -Norm 4109 (Federal Court of Justice, judgment of June 14, 2007 - VII ZR 45/06).
With a further decision of principle, the Federal Court of Justice is continuing this case law also for condominiums (Federal Court of Justice, judgment of June 4, 2009 - VII ZR 54/07). Analogous to the semi-detached house, noise protection levels II and III of VDI guideline 4100 or supplement 2 to DIN 4109 can be viewed as generally recognized rules of technology for an apartment that should meet the usual quality and comfort standards. The court makes it clear that the reference to DIN 4109 in the service description alone is not sufficient for its effective agreement as contractually owed noise protection. Rather, the entrepreneur who wants to deviate from the usual quality and comfort standards for apartments must also adequately inform the purchaser about the consequences of simple soundproofing construction for the later quality of living.
Both decisions are based on previous jurisprudence that the use of a certain service also owes its intended success. As early as the 1990s, new buildings were built using in-situ concrete and partly soundproofing plaster, which was then divided into classes by VDI 4100 in 1995. In the case of claims for a guarantee , liability would then also arise in the event of deficiencies in the noise protection to be expected (BGH decisions 1998 and 1999). The quality agreement did not have to explicitly list the expected sound insulation, so that sound insulation expected using the old DIN parameters also becomes a normal part of the construction contract, provided that it can be carried out in accordance with the generally recognized rules of technology . Uncertainties about the generally recognized rules of technology were cleared up by the later BGH decisions and make high-quality noise protection the basic assumption for new buildings.
- Dieter Ansorge: Soundproofing. Fraunhofer IRB, Stuttgart 2011, ISBN 978-3-8167-8395-4 (= botched building , volume 7).
- Elmar Sälzer, Georg Eßer, Jürgen Maack, Thomas Möck, Markus Sahl: Sound insulation in building construction: basic terms, requirements, constructions, evidence. John Wiley & Sons, 2014, ISBN 978-3-4330-3029-5 .
- Dieter Zimmermann, Roland Kurz: Damage-free building Volume 27: Inadequate soundproofing of buildings. Fraunhofer IRB, 2003, ISBN 978-3-8167-5797-9 .
- Alexander Müller: Noise protection in practice. Fraunhofer IRB, 2009, ISBN 978-3-8167-7967-4 .
- Quiz - questions about sound insulation
- Structural and subsequent sound insulation
- DIN 4109-1 | 2018-01 - Soundproofing in building construction - Part 1: Minimum requirements
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