This thesis examines regulation regarding sound insulation against road noise in DIN 4109. Since 1944 five Issues of this norm have been released. Requirements for noise protection against outside noise were first issued in 1989. In the following versions these requirements were rendered more precisely. These latest changes ensure a sufficient level of noise protection at night-time, as well as making specifications accurate to one decibel instead of having 5-dB steps.
The standard calculation of the sound insulation, using sound reduction indices and A-weighted sound pressure levels, results in problems, since both external noise and sound insulation are frequencydependent quantities. This inaccuracy gets currently compensated in the norm by a hidden correction value. It was initially questionable whether this value is still applicable, or whether further adjustments are needed.
If one considers the development of vehicle technology, which provides the relevant source of sound in road traffic, one notices that the requirements for sound emission have increased and significant technical changes have taken place on the vehicles themselves. In addition, the overall number of vehicles has changed. All in all, it is likely that the spectrum adjustment calculations based on measurements from the 1980s no longer provide correct results.
To review this uncertainty, road traffic spectra were measured according to standards at ten measuring positions, and the measurement results compared with other road traffic spectra. Spectra from the time of the development of spectrum adaptation in DIN 4109 were used for comparison, as well as current measurements from the summer of 2018. It was found that modern road traffic spectra are significantly less low frequency than 30 years ago.
The subsequent computation of correction values with the new spectra also provided significantly lower results than those known from the standards. In addition, an analysis of the effects of traffic spectra, sound insulation and the choice of the frequency range on the calculation of the correction values took place.
As another result, it can be stated that the undifferentiated consideration of the frequency composition of external noise and sound insulation used in DIN 4109 is no longer up-to-date and leads to several dB oversizing. However, a differentiated calculation based on current measurements would keep the singlenumber calculation possible and lead to appropriate values for the design of sound insulation of external building elements.
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This thesis examines regulation regarding sound insulation against road noise in DIN 4109. Since 1944 five Issues of this norm have been released. Requirements for noise protection against outside noise were first issued in 1989. In the following versions these requirements were rendered more precisely. These latest changes ensure a sufficient level of noise protection at night-time, as well as making specifications accurate to one decibel instead of having 5-dB steps.
The standard calculation...
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