Glass & transparentBroadband absorber

Physikalisch-Technische Bundesanstalt

Source: Manufacturer's product sheet

Value from the PTB table, not verified

Kaefer Microsorber micro-perforated polycarbonate foil

Microsorber

PTB reference data

Original description

Material properties

Manufacturer: Kaefer Isoliertechnik

Thickness: 0 in

Wall distance: 1.2 in, 2 in, 3.9 in

Hole size: 0 in

Up to fire class: not easily flammable, building material class B1

Reverberation chamber (ASTM C423 / ISO 354)· 5 variants

NRC

0.65

α_p per octave band

f (Hz)	125	250	500	1k	2k	4k
α_p	0.10	0.40	0.75	0.65	0.75	0.60

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		Value
3.9 in	zweilagig / 1.2 in Abstand zwischen den Folien	NRC0.65
2 in	zweilagig / 1.2 in Abstand zwischen den Folien	NRC0.60
3.9 in	einlagig	NRC0.40
2 in	einlagig	NRC0.35
1.2 in	einlagig	NRC0.25

NRC: 0.65 (derived from ISO 354 lab data)

Weight / density: 0,14 kg / m"

Dimensions: width: 1000 and 47 in

Measured values as a table (5 measurements)

Kaefer Microsorber micro-perforated polycarbonate foil: sound absorption coefficient αs per ISO 354 by frequency and test build-up
Build-up	NRC	100 Hz	125 Hz	160 Hz	200 Hz	250 Hz	315 Hz	400 Hz	500 Hz	630 Hz	800 Hz	1000 Hz	1250 Hz	1600 Hz	2000 Hz	2500 Hz	3150 Hz	4000 Hz	5000 Hz
0,105 mm · 0,14 kg / m" · 30 mm · einlagig	0.25	0.03	0.01	0.01	0.02	0.03	0.03	0.04	0.05	0.10	0.15	0.29	0.41	0.58	0.63	0.66	0.63	0.48	0.39
0,105 mm · 0,14 kg / m" · 50 mm · einlagig	0.35	0.03	0.03	0.03	0.04	0.04	0.07	0.16	0.26	0.40	0.53	0.64	0.63	0.62	0.53	0.40	0.25	0.31	–
0,105 mm · 0,14 kg / m" · 100 mm · einlagig	0.40	0.04	0.03	0.05	0.09	0.12	0.24	0.37	0.47	0.60	0.65	0.62	0.55	0.44	0.38	0.51	0.50	0.51	0.53
0,105 mm · 0,14 kg / m" · 50 mm · zweilagig / 30 mm Abstand zwischen den Folien	0.60	0.05	0.03	0.05	0.12	0.18	0.27	0.43	0.59	0.66	0.72	0.81	0.71	0.74	0.79	0.84	0.77	0.57	0.45
0,105 mm · 0,14 kg / m" · 100 mm · zweilagig / 30 mm Abstand zwischen den Folien	0.65	0.09	0.09	0.16	0.23	0.39	0.63	0.69	0.73	0.76	0.68	0.66	0.64	0.69	0.76	0.76	0.72	0.59	0.43

Measured values as a table (5 measurements)

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Last updated: 09/04/2026