Fraunhofer IBP micro-perforated metal cassette

PTB reference data

Original description

Material properties

Manufacturer: Fraunhofer IBP

Wall distance: 50 mm, 100 mm, 200 mm, 400 mm

Perforation: <1%

Hole size: 0.5 mm

Application: suspended ceiling

ISO 354 – reverberation chamber· 4 variants

α_w

0.35

α_p per ISO 11654

f (Hz)	125	250	500	1k	2k	4k
α_p	0.35	0.60	0.65	0.40	0.35	0.15

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Measured values as a table (4 measurements)

Fraunhofer IBP micro-perforated metal cassette: sound absorption coefficient αs per ISO 354 by frequency and test build-up
Build-up	α_w	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
50 mm	0.30	0.03	0.05	0.05	0.07	0.10	0.17	0.23	0.40	0.62	0.70	0.70	0.63	0.48	0.38	0.27	0.18	0.15	0.12
100 mm	0.30	0.06	0.07	0.12	0.22	0.28	0.46	0.61	0.67	0.71	0.67	0.55	0.41	0.34	0.30	0.27	0.18	0.18	0.09
200 mm	0.35	0.18	0.38	0.42	0.50	0.65	0.72	0.74	0.66	0.52	0.37	0.41	0.49	0.43	0.35	0.28	0.22	0.16	0.12
400 mm	0.35	0.33	0.61	0.76	0.70	0.68	0.60	0.44	0.39	0.50	0.45	0.47	0.46	0.46	0.37	0.32	0.23	0.15	0.12

Measured values as a table (4 measurements)

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Last updated: 28/08/2026