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| Acoustic
Noise
Reduction |
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Foam
materials, especially those with interconnected pores, absorb
sound in the following manner: incoming sound is reflected inside
the foam among the pores; the pore surfaces vibrate converting the
sound energy into heat. A considerably reduced sound level is
reflected back into the enclosed space.
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| Test method:
Measurement in an impedance
tube with diameter of 99 mm and 29 mm. Type 4002 fy. Brüel&Kjaer,
according to DIN 52215 (incidence angle 0")
Trial Sample:
Alulight® with an
open porisity and the density of 480 kg/m3 was
used. The thickness of the test specimen was 8,4 mm. |
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| Summary
of Results: |
Main Applications: |
- Alulight®
provides high values of the sound absorption coefficient at low
frequencies for a relatively wide frequency range
- the
finer the porosity and the more interconnected pore structure,
the higher the sound absorption
- maximum
sound absorption for preferred frequencies can be adjusted by
the size of the air gap between the Alulight®-plate
and a solid background (enlarging the air layer shifts the
maximum toward lower frequencies).
- the
combination of two Alulight®-plates extends the frequency range
of the high sound absorption coefficient
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- for
sound absorption under difficult conditions (elevated
temperature, moisture, dust, flowing gas, vibrations)
- for
sound absorption in sterile (antiseptic, dust free) environment
- for
sound absorption in structures where non inflammability is
important (e.g. airplanes, hotels, commercial and industrial
buildings)
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