? 0 1 Sound insulation and truth of insulating glass
The room at home is close to the road, and the traffic is very noisy. Many home improvement owners want to install a door and window that can isolate noise. This is of course correct. A good door and window can reduce the noise outside the road from 70 decibels to below 40 decibels.
However, don't be fooled by the "good sound insulation effect of insulating glass" of the merchants! Brother Peng tells you that the biggest function of insulating glass is energy saving, heat insulation and frost prevention. The actual sound insulation function is not even the same as that of single-layer glass with thickness. ?
Shocking. It's hard to believe! Brother Peng will use what he has learned all his life to tell you how to compare the sound insulation capabilities of five kinds of sound insulation glass (hollow, laminated, single-layer hollow laminated, double-layer hollow laminated and vacuum glass) commonly used in home improvement doors and windows, and tell you who is the real king of sound insulation. ?
? What are the four knowledge points that must be learned to compare the sound insulation effect?
Before comparing the sound insulation effects of different glasses, we should first understand these four things:
1. How does the human ear hear sound?
Sound is a kind of pressure wave: when automobile tires rub against the road surface and automobile horn, their vibration will cause the medium-air molecules to vibrate rhythmically, which will change the density of the surrounding air and form longitudinal waves with alternating density, thus generating sound waves. This phenomenon will continue until the vibration disappears. ?
Sound is transmitted through media, and gas, liquid and solid can all transmit sound. Vacuum can't transmit sound.
As a kind of wave, the frequency and amplitude of sound have become important attributes to describe waves, and the frequency corresponds to what we usually call pitch (the band that human ears can hear is 20~20000 Hz, 200~6000Hz is the intermediate frequency, the most sensitive band is 500~8000 Hz, and the noise band that makes traffic noise uncomfortable is concentrated between 125Hz~750Hz). ?
? 2. Coincidence effect
Every kind of glass has the coincidence effect of sound insulation performance, that is, a sound wave can easily penetrate the glass in a certain frequency band. The purpose of noise reduction and vibration control is to find that the acoustic frequency of coincidence effect is not within the frequency range that needs noise reduction.
For example, the matching effect of insulating glass appears in the middle and low frequency bands, so the ability to isolate traffic noise is not good. The matching effect of laminated glass appears around 3000 Hz, which is far away from the traffic noise in the middle and low frequencies and has a good performance on traffic noise. ?
3. Law of quality?
The greater the interlayer thickness, the greater the sound transmission loss. In other words, the greater the thickness of glass, the stronger the sound insulation ability. Usually, the noise can be reduced by 6 decibels every time the glass thickness increases by 1 time. ?
? 4. China's current national standard is GB 3096-2008 "Sound Environment Quality Standard"?
The noise pollution standard of residential buildings mainly refers to 1 class and class 2 standards, and the high-grade villa area can refer to class 0 standard.
? Comparison of five kinds of glass sound insulation: hollow, sandwich, single-layer hollow sandwich, double-layer hollow sandwich and vacuum.
When you roughly read the above knowledge points about sound insulation, you can intuitively understand how different glasses sound insulation:
Insulated glass: air is used to partially absorb the energy of medium and high frequency acoustic vibration, thus reducing the sound level of sound waves. Its isolation performance is related to the thickness of glass, the gas composition of spacers, the number and thickness of spacers. ?
Laminated glass: PVB glue layer is mainly used to absorb medium and low frequency sound waves and control the transmission of sound energy. The properties are related to the actual thickness of glass, the thickness of laminated film and the flexibility of laminated film. It is worth noting that in the cold winter, the interlayer of laminated glass will lose its elasticity due to the temperature (the chewing gum in winter is frozen like a popsicle), thus the noise reduction effect is greatly reduced. ?
Sandwich insulating glass has the functions of the above two kinds of glass. ?
Vacuum glass: Sound insulation is achieved by using the principle that sound waves cannot be transmitted due to lack of medium in vacuum environment. Theoretically, it can be completely soundproof (but it is not a real sound insulation glass, because the transparent supporting base added in the manufacturing process is equivalent to a solid medium, which provides a shortcut for sound wave propagation). ?
In order to make the comparison more scientific, Peng Ge specially found a test data of American Riverbank Acoustics Laboratory. ?
The sound transmission loss of single-layer glass, laminated glass, insulating glass and laminated insulating glass of various specifications measured by this data, the higher the score (STC OITC RW), the better the sound insulation! ?
It can be concluded that the sound insulation effect of vacuum glass is > > double-layer sandwich hollow > single-layer sandwich hollow > sandwich glass > insulating glass (insulating glass scores lower than single-layer glass). ?
Conclusion: sound insulation glass has the best cost performance?
Although the data has proved the sound insulation effect of each kind of glass, the order of Peng Ge's recommendation to sound insulation glass is: hollow laminated glass >; Laminated glass > insulating glass > vacuum glass. ?
Because in actual use and purchase, you also need to consider factors such as cost performance and heat insulation. ?
For example, although vacuum glass can completely isolate noise in theory, the vacuum glass currently available on the market has a large number of fulcrums between the glasses, so its sound insulation ability is greatly reduced. This makes a square meter of thousands of vacuum glass look very low cost-effective. ?
Another example is PVB film, which is usually used for laminated glass. The thermal conductivity at room temperature is 0.22 1(W/km), and that of air is 0.024, which is ten times different. The intuitive feeling brought by thermal conductivity is just like using a porcelain bowl (PVB) and a wooden bowl (air) when eating. The insulation of single-layer laminated glass is not ideal, which also needs to be considered when choosing doors and windows. ?
Brother Peng recommends several glass combinations here. You can choose the most cost-effective solution according to the sound insulation demand and price:
1. strongest version: 5+1.14pvb+5+12a+5+1.14pvb+5?
2. The most cost-effective version: 6+1.14pvb+6+12a+6,5+1.14pvb+5+12a+5?
3. Ordinary sound insulation version: 6+ 1. 14PVB+6?
Finally, Brother Peng reminded me that in addition to the main factors of product types, installation, sealing effect of windows, types of gaskets and buffer media of glass and window frames are all very important factors to reduce noise. ?
References: Ding, Wang Xinchun, Sound insulation performance and noise reduction design of glass. Glass, Judas, 2006, handbook of noise and vibration control. Machinery Industry Press, 2002, Zhu Jun, energy-saving and safe insulating glass and its selection. Architectural glass and industrial glass, 20 13.
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