Vacuum insulating glass soundproof performance

We’re living in the world full of noise,some noise seriously affects the quality of human life. Urban noise is mainly divided into domestic noise, traffic noise, equipment noise and construction noise.Glass,not only fulfill people visual,safety,water&wind resistant requirement, but also work as barrier to stop noise.

The vacuum insulating glass,has the best soundproof performance compared with other glass products,this post will introduce the noise type,how to decrease noise and why vacuum insulating glass has high acoustic performance.

Noise classification

In architectural acoustics, the sound can be classified into below :

• 200-300Hz:Low-frequency soun
• 500-1000Hz:middle-frequency sound.
• 2000-4000Hz or above:high-frequency sound

In the frequency range that human ears can hear, low- and medium-frequency noise is the most common, such as car noise on highways and rail traffic noise. Therefore, improving the glass sound insulation performance against medium and low frequencies is both a difficulty and an important point.

How to measure the glass soundproof performance?

The sound insulation performance of glass is measured by weighted sound insulation Rw or STC (Sound Transmission Class), in decibels (dB).

Analyzing the sound insulation of glass requires understanding the laws governing the sound insulation performance of glass, the relationship between the human ear’s subjective perception of sound and the weighted sound insulation, and then the reasonable glass structure can be configured to obtain the best sound insulation effect.

Factors affect glass acoustic performance

The sound insulation of glass has a logarithmic function relationship with the weight of the glass and the frequency of the sound:

R=20lgM+ 20lgf-47.2(dB)

R——The sound insulation of glass, dB;

M——The unit area weight of glass, kg/m²;

f——The frequency of incident sound, Hz.

The only thing related to the glass is the glass unit weight , which shows that the thicker the glass, the better the sound insulation effect.That’s the reason why glass used in airport or highway are always triple glass units with total thickness over 50mm.

Beside that ,interlayer used in laminated glass,gas filled and spacer thickness in insulated glass also affect the glass overall sound performance.

Learn more:How to increase glass sound transmission loss

Typical glass soundproof performance

Below tables shows typical sound transmission loss ,which showed factors affect glass acoustic performance:

Glass Type	Thickness	STC	OITC
3 C	3	28	22
12 C	12	36	21
6+0.76+6	12.76	36	32
6+0.76 acoustic PVB+6	12.76	39	34
6+12A+6	24	34	29

12mm monolithic glass STC is 8Dbs higher than 3mm,based on same thickness,the OITC of laminated is 11Dbs higher than monolithic glass.Taking advantage of acoustic PVB products,the sound transmission loss and be further increased to get quiet environment.

How vacuum insulating glass block sound?

The vacuum glass is composed of two pieces of glass sealed with metal or glass material, and a space of 0.15mm/0.3mm thickness is separated by a micro support in the middle. This space is evacuated to reach a vacuum degree of less than 10-2Pa.

The structure has three main characteristics:

1. There is a vacuum layer between the two pieces of glass, which eliminates the medium required for sound propagation;
2. The existence of the support becomes the only sound transmission channel in vacuum insulating glass.The bigger supporter distance,the less support pillars,the better sound acoustic performance.
3. The 0.3mm vacuum space is quite thin,which caused the high glass resonance frequency , and it has been completely moved out of the middle and low frequency range.

Vacuum insulating glass has an weight transmission loss of 39Dbs.

Features of VIG transmission loss

Vacuum glass has a higher sound insulation in the low frequency range. This is mainly because the four sides of vacuum glass are rigidly connected, so it has stronger resistance to deformation and greater stiffness than other forms of glass.

The weighted sound insulation of vacuum glass at 100-5000Hz (including low, medium and high frequency) is 2dB higher than that of insulating glass;

In the calculation of weighted sound insulation of 100-1000Hz (including low and intermediate frequencies), the weighted sound insulation of vacuum glass 4dB higher than insulating glass. Laminated glass and vacuum glass have similar performance at low and medium frequencies, and both are significantly higher than insulating glass.

Glass Structure	100	125	160	200	250	315	400	500	630	800	1000	RW
5+0.3V+5	29.7	28.5	27.9	28	29.9	32.5	34.1	34.9	36.2	38.2	39.2	40
6+12A+6	27	24	29	22	22	22	30	33	35	38	40	36
5+0.76PVB+5	27	27	27	30	31	31	33	34	35	36	36	39

Summary:

Vacuum insulating glass soundproof performance is similar as laminated glass,but it has much better performance in low and middle frequency,especially traffic noise.

With the use of tempered vacuum insulating glass, the room is as quiet as a library even if it is next to an airport, viaduct or main road.

The advantages of vacuum glass used as window glass include thin thickness and small space occupation. Especially for window glass renovation projects, the sound insulation performance of the window can be improved without changing the profile structure. The biggest advantage of vacuum glass is that it has strong thermal insulation performance under the premise of superior sound insulation performance. This is far beyond that of laminated glass and insulating glass.

HaanGlas is your turnkey vacuum insulating glass manufacturer in China,kindly contact us if you want a silent working&living environment through adopting VIG in your windows.