GlazingWall (window)

Double Glazed Unit (IGU) Acoustic Properties \u2014 Absorption Coefficients (125Hz\u20134kHz)

Insulated glass unit (IGU) with two panes and gas-filled cavity. Thermal performance is excellent but acoustic absorption is minimal. The sealed air cavity provides some low-frequency panel absorption but mid-high frequency performance is essentially reflective.

NRC
0.10
αw
0.10
Applications
Wall (window)
NRC (Noise Reduction Coefficient)
NRC is the arithmetic average of sound absorption coefficients at 250, 500, 1000, and 2000 Hz, rounded to the nearest 0.05. Double Glazed Unit (IGU) has an NRC of 0.10.
Reference: ASTM C423 / ISO 354:2003

Absorption Coefficients by Octave Band

Frequency (Hz)125250500100020004000
α (absorption)0.150.050.040.030.020.02
125 Hz
0.15
250 Hz
0.05
500 Hz
0.04
1000 Hz
0.03
2000 Hz
0.02
4000 Hz
0.02

RT60 Impact

Double glazing is primarily reflective. Large glass facades require compensating ceiling/wall absorption to control RT60

Manufacturers & Brands

PilkingtonGuardian

Frequently Asked Questions

What is the NRC of Double Glazed Unit (IGU)?

Double Glazed Unit (IGU) has an NRC (Noise Reduction Coefficient) of 0.10, calculated as the arithmetic mean of absorption coefficients at 250, 500, 1000, and 2000 Hz per ASTM C423.

Where is Double Glazed Unit (IGU) typically used?

Double Glazed Unit (IGU) is typically used as a wall (window) treatment. Insulated glass unit (IGU) with two panes and gas-filled cavity.

How much does Double Glazed Unit (IGU) reduce RT60?

Double glazing is primarily reflective. Large glass facades require compensating ceiling/wall absorption to control RT60

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