glass window 0.68 kg/m² (series 3)

PTB reference data

Original description

Material properties

Surface weight: 0.68 kg/m²

Reverberation chamber (ASTM C423 / ISO 354)

NRC

0.05

derived from ISO 354 lab data

α_p nach ISO 11654

f (Hz)	125	250	500	1k	2k	4k
α_p	0.10	0.05	0.05	0.05	0.05	0.05

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Value from the PTB table, not verified

NRC: 0.05 (derived from ISO 354 lab data)

Measured values as a table (1 measurement)

glass window 0.68 kg/m² (series 3): sound absorption coefficient αs per ISO 354 by frequency and test build-up
Build-up	NRC	63 Hz	125 Hz	250 Hz	500 Hz	1000 Hz	2000 Hz	4000 Hz	8000 Hz
Measurement 1	0.05	0.15	0.10	0.05	0.04	0.03	0.03	0.03	0.03

Measured values as a table (1 measurement)

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Last updated: 09/04/2026