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<< Click to display Table of content >> Reflection and materials |
  
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<< Click to display Table of content >> Reflection and materials |
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Materials A0, A1, A2, A3, A4 are used for facade and noise barriers. This classification used in MithraSIG for materials is consistent with the classification of the old version of the standard EN 1793-1 (Test method for determining the acoustic performance - Part 1: Intrinsic characteristics of sound absorption under diffuse sound field conditions). This is a result of Harmonoise and Imagine EU projects.
Absorption Coefficients / Frequency (Mhz) |
50 |
63 |
80 |
100 |
125 |
160 |
200 |
250 |
315 |
400 |
500 |
630 |
800 |
1000 |
1250 |
1600 |
2000 |
2500 |
3150 |
4000 |
5000 |
6300 |
8000 |
10000 |
A0 (very reflective) |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
0 |
A1 (reflective) |
0 |
0 |
0 |
0 |
0 |
0.1 |
0.1 |
0.1 |
0.1 |
0.1 |
0.1 |
0.1 |
0.2 |
0.2 |
0.2 |
0.2 |
0.3 |
0.3 |
0.4 |
0.4 |
0.4 |
0.4 |
0.4 |
0.4 |
A2 (medium) |
0.1 |
0.1 |
0.1 |
0.2 |
0.2 |
0.2 |
0.3 |
0.3 |
0.4 |
0.4 |
0.5 |
0.5 |
0.6 |
0.6 |
0.7 |
0.7 |
0.7 |
0.8 |
0.8 |
0.8 |
0.8 |
0.8 |
0.8 |
0.8 |
A3 (absorbent) |
0.2 |
0.3 |
0.3 |
0.4 |
0.4 |
0.5 |
0.6 |
0.6 |
0.7 |
0.8 |
0.8 |
0.9 |
0.9 |
0.9 |
0.9 |
0.9 |
0.9 |
0.9 |
0.9 |
0.9 |
0.9 |
0.9 |
0.9 |
0.9 |
A4 (very absorbent) |
0.4 |
0.4 |
0.5 |
0.6 |
0.7 |
0.8 |
0.9 |
0.9 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
1 |
0.9 |
0.9 |
0.9 |
0.9 |
0.9 |
0.9 |
0.9 |
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In acoustic, absorption performances are independent of transmission performance. |
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In the standard ISO 9613-2, a screen must have a closed surface and have a mass area of at least 10 kg / m²; the other standards do not say anything, but implicitly a screen must have a sound reduction index at least equal to its diffraction performance. So at least 10 dB, but 15 dB is better!
MithraSIG does not calculate transmission through noise barriers.
