FabricHighly absorbent
Data source
PTB reference data
Physikalisch-Technische Bundesanstalt
Source: C.M.Harris, Noise Control in Buildings, McGraw Hill 1994
Value from the PTB table, not verified
Armstrong Type 3301 cloth-faced fiberglass lay-in panel, painted
Type 3301
PTB reference data
Original description
Armstrong Type 3301 cloth-faced fiberglass lay-in panel, painted
Material properties
Manufacturer: Armstrong World Industries
Thickness: 3/4 inch
Wall distance: 16 in
Surface: painted
Measurement data
Sound absorption
Reverberation chamber (ASTM C423 / ISO 354)· 2 variants
NRC
0.85
Frequency values
αp per octave band
| f (Hz) | 125 | 250 | 500 | 1k | 2k | 4k |
|---|---|---|---|---|---|---|
| αp | 0.70 | 0.85 | 0.60 | 0.85 | 0.95 | 1.00 |
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| Compare | Value | |
|---|---|---|
| 0.35 lb/ft² | NRC0.85 | |
| 0.4 lb/ft² | NRC0.75 |
NRC: 0.85 (derived from ISO 354 lab data)
Dimensions: 24 x 48 inches
Distance: 16 in
Measured values as a table (2 measurements)
| Build-up | NRC | 125 Hz | 250 Hz | 500 Hz | 1000 Hz | 2000 Hz | 4000 Hz |
|---|---|---|---|---|---|---|---|
| 3/4 inches · 0.4 lb/ft² · 400 mm | 0.75 | 0.48 | 0.35 | 0.71 | 0.96 | 1.05 | 1.04 |
| 3/4 inches · 0.35 lb/ft² · 400 mm | 0.85 | 0.71 | 0.87 | 0.62 | 0.86 | 0.96 | 1.07 |
Measured values as a table (2 measurements)
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