To help reduce noise pollution
Noise is a common nuisance that can easily penetrate our environments, from the occasional emergency siren disrupting your sleep to the constant traffic noise while you work. Research has shown that noise can negatively impact your health and overall quality of life. By enhancing sound insulation, glass can help reduce unwanted sounds, transforming your buildings into quiet, serene spaces.
In general, the thicker or heavier the glass, the greater the noise reduction. Therefore, sound reduction efficiency increases as glass thickness increases. However, the use of laminated glass provides further benefits of acoustic insulation. When replacing a single glass pane with a laminated pane, with the same overall thickness, the sound insulation is significantly improved.
Laminated glass consists of two or more layers of glass that are permanently bonded together with one or more polymer interlayers using heat and pressure. Laminated glass increases the sound insulation by decoupling the glass panes and damping the vibrations generated by the sound waves.
See in this video how laminated glass is made:
Special acoustic PVB interlayers are also available for further improving the sound control performance of glass. These products consist of a multi-layer construction using standard PVB with a special soft acoustic core:
The primary benefit of acoustic glass is its effectiveness in reducing sound transmission. It helps to reduce external noises such as traffic, construction, and street sounds, while also minimizing internal noise within a building. This results in a quiet and serene indoor environment, which can improve comfort, productivity, and focus.
When subjected to sufficient impact force, laminated glass might break. However, the glass fragments tend to adhere to the plastic interlayer, helping to reduce the risk of injury due to fragments of broken glass. Specific laminated glass make-ups can be used for applications that require anti-intrusion or forced-entry security, as well as for ballistic and blast mitigation, or hurricane resistance.
Laminated glass can absorb up to 99% of harmful UV rays, which are responsible for up to 50% of interior surfaces fading. This protection helps keep interior surfaces and furniture looking like new longer.
When combined with high-performance or low-E coatings, laminated glass can help improve the energy efficiency of buildings by providing thermal insulation and/or solar control properties.
Acoustic rating can be used to measure sound insulation of building elements and varies depending on the region of the world. For example, Rw is used in Europe while OITC and STC ratings are used in North America. Other regions may use one option or the other.
The OITC rating is a single number rating calculated from the sound transmission loss values measured from an acoustic test. It is calculated based on ASTM E 1332 using sound transmission loss data measured between 80 – 5000 Hz. The low frequency level represents the sound waves from the outside of a building such as those of road and rail traffic, and of nearby aircraft take-offs. OITC rating is recommended for exterior glazing.
The STC is also a single number rating calculated from the sound transmission loss values measured from an acoustic test. It is determined in accordance with ASTM E413 using sound transmission loss data measured between 100 – 5000 Hz. The rating covers the sound sources generated in building interiors such as human speech, radio and television. STC rating is recommended for interior glazing.
The most commonly used measure in Europe is the average noise reduction factor, also known as Rw. We apply additional correction factors to the Rw that represent the deviations of sound insulation depending on the sound source.
The Rw represents the overall index (dB), the C represents the correction factor for higher frequencies and the Ctr represents the correction factor for lower frequencies (typical traffic noise).
Depending on the noise source, the correct glazing should be selected by considering if it’s exposed to low frequencies or high frequencies.
In this example, the reduction factor is –1 db, which gives a total acoustic value of 41 dB, and the reduction factor Ctr is –5 dB which gives a total acoustic value of 37 dB.
Rw = 42 (-1; -5) | |
Rw | = 42 dB |
Rw +C = 42 - 1 | = 41 dB |
Rw +Ctr = 42 - 5 | = 37 dB |
The sound control properties of glazing can be estimated using computer models. Different software exists for estimating the acoustic performance of different types of glazing.
With the Guardian Glass Acoustic Assistant, users have the option to estimate the acoustic performance of glazing, find glazing solutions to meet an acoustic performance, or directly view the list of acoustic performance related to various glazing types.
The estimation of acoustic performance is based on component-similarity assumptions which are derived from measured data and interpolation. In this approach, it was possible to expand the database of values from test certificates. It’s important to remember that currently there are no standards that describe how to estimate the acoustic ratings for glazing.
Guardian Glass offers you a wealth of technical notes, tools – including the Acoustic Assistant – and online learning to enhance your knowledge about glass and help you specify the most appropriate glass for your project. Visit our Resource Hub to learn more!
Many parameters influence the overall acoustic performance of a building envelope such as the framing system, sealing, installation of glazing and others. Regarding the glazing, the most important to mention, in addition to the glass thickness and the use of laminated glass are:
An option to optimize the acoustic performance of glazing is to use different glass thicknesses in a glazing composition. The different thickness of each glass pane in a glazing unit minimizes resonance effects due to the thickness differences of the glass components.
The interspace of insulating glass units muffles the vibrations from the outer pane before they reach the inner second pane. Therefore, the greater the interspace, the better the noise reduction. Bear in mind that the larger air space increases the overall glazing thickness and impacts thermal insulation performance.
It is important to note that heat-treatment, coatings, and ceramic frit DO NOT impact the final acoustic estimation.
"When aiming to reduce noise levels in a building, selecting the right type of glazing is crucial. However, it's also important to consider other elements of the building façade that can influence the overall acoustic performance. Factors such as the materials used and the design of the façade play roles in helping to achieve optimal sound insulation. By taking a holistic approach and addressing all these aspects, you can help reduce unwanted noise effectively and create a quiet, comfortable indoor environment."
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