Noise barrier
A noise protection wall is a structure that attenuates noise emanating from a sound source (e.g. roads, railways, factories) in such a way that it is insulated to such an extent at an immission point to be protected (e.g. residential buildings, hospitals) that the legal limit values are observed. When used at the emission site, noise barriers and walls are considered active noise protection. These can be supplemented by passive noise protection measures (e.g. soundproof windows ).
definition
Noise barriers are used in the context of noise protection on streets. They can be individually modeled and thus integrated well into the landscape. They can be planted and you can use the necessary soil from the excavated road construction or fill the wall with substitute building materials. Therefore, the construction costs are lower than for soundproof walls. In addition, unlike soundproof walls, walls do not reflect the sound. Another advantage over soundproof walls is the usability of the side facing away from the noise source. Walkways and bike paths, garages or graves can be integrated there.
A disadvantage of noise barriers is the large area required. In the case of new planning, it is possible and necessary to secure the space for noise protection devices in the development plan (Section 9 (1) No. 24 BauGB), even if, for example, B. a road is to be built later.
Another disadvantage compared to noise barriers is that the noise protection is lower at the same height, since the screen edge (highest point of the wall) is further away from the noise source. However, this can be compensated for by a higher embankment. For optical reasons, soundproof walls are usually preferable to corresponding walls.
Legal basis
The construction of a noise protection wall is both a noise remediation measure and noise prevention. The legal requirements for noise abatement are summarized in the “Guidelines for Traffic Noise Protection on Federal Highways in the Federal Construction Load” (VLärmSchR-97) in conjunction with the “Guidelines for Noise Protection on Roads - 1990 Edition” (RLS-90).
The basic prerequisites for noise abatement are that the " assessment level " of an area category exceeds one of the relevant immission values for noise abatement. The noise levels are calculated with the current traffic volume according to the procedure prescribed in RLS-90. In addition to usage, a distinction is also made between day and night loads in the area categories.
- For areas around hospitals, schools, spa and old people's homes, pure and general residential areas and small settlement areas, 67 dB (A) during the day and 57 dB (A) at night are the relevant immission values
- For core, village and mixed areas, the relevant values on federal trunk roads are 69 dB (A) during the day and 59 dB (A) at night. The values of 67 dB (A) during the day and 57 dB (A) at night apply on state roads
- In commercial areas, 72 dB (A) during the day and 62 dB (A) at night are decisive
Mode of action
Noise barriers have a noise-shielding effect; they partially prevent the sound from spreading . In this way, noise reductions of up to 20 dB (A) can be achieved. The reduction of 10 dB (A) is perceived as halving the noise level. The effectiveness of a noise barrier is influenced by the following factors:
- Height of the noise barrier
- Distance from the source of the noise (place of emission)
- Distance from the point of immission
- Height of the immission location
- Frequency spectrum of the sound
- Planting the wall
- Wind and temperature differences (affect sound waves)
- Diffraction effects on the upper edge
costs
As described above, noise barriers require a significantly larger floor area than noise barriers to achieve the same level of efficiency , which means that in many cases they cannot be used in urban areas. On feeder roads, country roads and expressways as well as motorway sections outside of cities, the construction of a noise protection wall is advisable for optical reasons, but above all for cost reasons.
When building a wall as part of noise prevention, the excavated road construction can be used directly and supplemented with sand, gravel or substitute building materials or secondary building materials.
In the case of noise remediation, the subsequent construction of a wall, you can work almost entirely with sand, gravel and substitute or secondary building materials (without the missing excavation). The use of incineration ash for the core of the wall is particularly cost-effective. An exemplary project for this process was the construction of a noise protection wall along the A44 near Kassel.
Individual evidence
- ^ Ministry of Transport and Infrastructure Baden-Württemberg
- ^ Westphalian Wilhelms University
- ^ State Office for Road Construction North Rhine-Westphalia
- ↑ Measures to reduce noise pollution. City of Leipzig
- ↑ Noise protection systems on roads - substitute building materials as a solution
- ↑ Basics for the use of RC building materials and HMV ash (PDF)
- ↑ Reference: Noise protection wall A44 Kassel. (PDF)