How to demonstrate the sound insulation of tempered glass
Information summary：The sound insulation core of tempered glass is reflected in three dimensions: material characteristics, structural design, and sound wave barrier principle. Its sound insulation effect not only depends on the performance of the glass itself, but also closely related to the thickness of the glass, interlayer structure, sealing process, etc. The specific manifestations of its sound insulation perfor
The sound insulation core of tempered glass is reflected in three dimensions: material characteristics, structural design, and sound wave barrier principle. Its sound insulation effect not only depends on the performance of the glass itself, but also closely related to the thickness of the glass, interlayer structure, sealing process, etc. The specific manifestations of its sound insulation performance are analyzed in detail from four aspects: sound insulation principle, core influencing factors, sound insulation performance in different scenarios, and practical application verification
1、 Core sound insulation principle: Block the "propagation path" of sound waves
Sound waves need to propagate through media such as air and solids, and tempered glass mainly blocks sound waves through the following methods:
Reflection and absorption: The surface of tempered glass is hard and smooth. When sound waves (air conducted sound) collide with the glass, some of the sound waves are reflected by the surface (especially high-frequency sound waves), and some of the sound waves are absorbed by the internal molecular vibrations of the glass (converted into heat energy), reducing the penetration of sound waves;
Damping effect: Tempered glass undergoes high-temperature quenching treatment, resulting in uniform distribution of internal stress and denser molecular structure. The glass vibration caused by sound wave propagation is prevented by internal stress (damping effect), reducing vibration transmission efficiency, especially weakening low-frequency sound waves (such as traffic noise and mechanical vibration);
Structural barrier: For composite tempered glass such as hollow or laminated glass, the middle air layer or film (such as PVB, EVA) will form an "acoustic barrier" - the air layer can block the direct transmission of sound waves, while the film absorbs sound wave energy through its own elasticity, further enhancing the sound insulation effect.
2、 Key influencing factors of sound insulation performance of tempered glass (intuitively reflecting sound insulation ability)
1. Glass thickness: The thicker the thickness, the stronger the sound insulation effect
The sound insulation performance of a single tempered glass is positively correlated with its thickness, and the core reason is:
An increase in thickness can enhance the surface density (mass per unit area) of glass. According to the "law of mass", the higher the surface density, the stronger the ability to block air borne sound;
The molecular vibrations of thick glass are more difficult to excite, especially the barrier effect on low-frequency sound waves (below 500Hz, such as truck roar and elevator running sound) is significantly improved.
2. Glass structure: Composite structure significantly improves sound insulation compared to single piece glass
The sound insulation effect of a single piece of tempered glass is limited (even with a thickness of 15mm, the RW is difficult to exceed 40dB). In practical applications, composite structures are often used, and the sound insulation is improved in a stepped manner:
Hollow tempered glass (double-layer/triple layer):
Structure: Two/three layers of tempered glass+middle air layer (thickness 12-20mm), partially filled with inert gas (such as argon);
Sound insulation performance: The air layer can block the direct transmission of sound waves and form a "mass spring mass" system with the glass, reducing the resonance frequency. The barrier effect on medium and low frequency noise (such as subway and high-speed rail sound) is 8-15dB higher than that of a single piece of glass;
Example: 5mm+12A+5mm insulated tempered glass, RW can reach 35-38dB, can block more than 80% of traffic noise, suitable for windows in residential and office buildings facing the street.
Laminated tempered glass (PVB/EVA interlayer):
Structure: Two layers of tempered glass+middle polymer film (thickness 0.76-2.28mm), composite by high temperature and high pressure;
Sound insulation performance: Film has high damping characteristics, which can strongly absorb sound wave energy (especially high-frequency noise), and the difference in elasticity between glass and film will break the sound wave propagation path. RW is 10-20dB higher than that of a single glass of the same thickness;
Example: 5mm+1.52mm PVB+5mm laminated tempered glass, RW can reach 38-42dB, can block more than 90% of high-frequency noise (such as car honking, crowd noise), suitable for hospitals, schools, and recording studios.
Hollow laminated composite tempered glass (such as 5mm+12A+5mm+1.52mm PVB+5mm):
Sound insulation performance: Combined with the low-frequency barrier of the hollow layer and the high-frequency absorption of the adhesive layer, the RW can reach over 45dB, effectively blocking strong noise environments such as high-speed trains and airports (such as reducing noise from 70dB to below 35dB within 500 meters of high-speed trains, achieving indoor quietness standards).
3. Sealing and installation process: Details determine the upper limit of sound insulation effect
Even if the glass itself has excellent sound insulation performance, if installed improperly and sealed, sound waves will penetrate through gaps ("sound bridge effect"), resulting in a significant decrease in sound insulation effect:
Sealing material: EPDM sealing strip and silicone structural adhesive are used to avoid the use of ordinary rubber strips (which are prone to aging and cracking, forming gaps);
Installation process: A reasonable gap (5-8mm) should be reserved between the glass and the window frame, filled with foaming agent and sealant. The gap between the window frame and the wall should also be sealed to prevent "sound transmission through gaps";
Intuitive impact: Well sealed insulated tempered glass has a 5-10dB improvement in sound insulation compared to poorly sealed glass (if not sealed, the 60dB noise outside the window can be reduced to 45dB indoors, and after sealing, it can be reduced to 35-40dB).
3、 Sound insulation performance in different scenarios (close to actual usage needs)
1. Civil building scenes (residential buildings, office buildings, hospitals)
Requirement: Block traffic noise (cars, subways, high-speed trains), crowd noise, and equipment noise (air conditioning outdoor units, elevators);
Sound insulation performance:
Street facing residential buildings: Using 12mm thick single piece tempered glass or 5mm+12A+5mm insulated tempered glass can reduce outdoor traffic noise from 65-70dB to below 40dB indoors (in accordance with the "Quiet Standard" of the "Code for Design of Sound Insulation of Civil Buildings" GB 50118);
Hospitals/schools: Using laminated tempered glass (such as 5mm+1.52mm PVB+5mm) can reduce outdoor noise levels from 55-60dB to below 35dB indoors, meeting the quiet needs of diagnosis, treatment, and teaching;
Office building: Hollow laminated composite tempered glass (such as 5mm+12A+5mm+1.52mm PVB+5mm) can block office equipment noise (printers, air conditioning) and outdoor traffic noise, ensuring a quiet office environment.
2. Industrial and special scenarios (factories, recording studios, buildings near airports)
Requirement: Block industrial machinery noise (machine tools, fans), strong traffic noise (airport takeoff and landing sound, high-speed rail roar), and high-frequency noise (equipment operation sound);
Sound insulation performance:
Industrial plant: choose tempered glass with a thickness of over 15mm or three-layer insulated tempered glass (5mm+12A+5mm+12A+5mm), with an RW of over 40dB, which can reduce more than 85% of mechanical noise and protect workers' hearing;
Recording studio/studio: using laminated tempered glass and professional soundproof window frames, with an RW of over 50dB, it can achieve "indoor and outdoor sound isolation" to avoid external noise interference with recording quality;
Buildings near the airport: Hollow laminated composite tempered glass (such as 6mm+16A+6mm+2.28mm PVB+6mm) is used, with an RW of 48-52dB, which can reduce the noise level of airport takeoff and landing from 80-85dB to below 40dB indoors, meeting the comfort level of living.
3. Transportation scenarios (cars, high-speed trains, ships)
Requirement: Block wind noise, engine noise, and track vibration noise;
Sound insulation performance:
Car windshield: commonly uses laminated tempered glass (such as 4mm+2.1mm PVB+4mm), with an RW of 38-42dB, which can effectively block wind noise (during high-speed driving) and engine noise, improving driving comfort;
High speed railway windows: using hollow laminated tempered glass (such as 5mm+10A+5mm+1.52mm PVB+5mm), with an RW of over 45dB, can reduce the 75-80dB noise during high-speed railway operation to below 50dB inside the carriage, ensuring passengers' rest.
4、 Quantitative standards and verification methods for sound insulation (professional reference)
1. Core quantitative indicator: Weighted Sound Insulation (RW)
Definition: According to relevant standards, a single value is obtained by integrating the sound insulation effects of different frequencies (100-3150Hz). The larger the value, the better the sound insulation effect;
Grading criteria:
Low sound insulation: RW ≤ 28dB (applicable to indoor partitions without noise interference);
Medium sound insulation: 28dB ＜ RW ≤ 35dB (applicable to buildings in low-noise areas);
High sound insulation: 35dB ＜ RW ≤ 45dB (applicable to buildings near streets and traffic arteries);
High sound insulation: RW>45dB (suitable for industrial, airport nearby buildings, and special places).
2. Actual verification method
On site inspection: Use a noise meter to measure the noise levels on both sides of the glass, calculate the sound insulation level (outer noise level - inner noise level), and conduct the inspection without any other sound transmission paths (such as door and window gaps, walls);
Laboratory testing: According to GB/T 16730 "Test Method for Sound Insulation Performance of Building Glass", the RW value is obtained by testing in a professional sound insulation laboratory, which can accurately reflect the sound insulation performance of the glass itself.
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