Noise under control
Noise in the modern world is a nuisance. It cannot be "turned down"; the only way to mitigate it is by using barriers such as walls or windows with high acoustic insulation.
ACOUSTIC INSULATION – WHAT IS IT AND WHY DOES IT MATTER?
Environmental pollution is not just about smog or acid rain. Other factors negatively affecting human well-being include excessive artificial light and noise. The latter can cause sleep disorders, impact the hormonal system, and increase the risk of hypertension and cardiovascular diseases. It also reduces concentration levels and triggers irritability—people in noisy environments are more prone to arguments and aggressive behavior. Increasingly stringent building material regulations aim to create acoustic comfort in our homes.
NOISE EVERYWHERE
Permissible noise levels are defined in regulations issued by ministers of infrastructure and construction. In built-up areas, daytime noise levels should not exceed 60 dB, while at night, they should not exceed 50 dB. Indoors, the maximum values are 40 dB during the day and 30 dB at night. Sound levels are described using the sound intensity level scale, expressed in decibels (dB). For reference:
The human hearing threshold is 0 dB.
A loud conversation reaches 60 dB.
A moderately busy road measures 70 dB.
An airport can reach 120 dB.
The pain threshold is at 130 dB.
However, the issue is that sound intensity, measured in decibels, follows a logarithmic scale. Our ears perceive changes in sound intensity in a nonlinear way. In simple terms, doubling the intensity increases the sound level by only 3 dB, a tenfold increase raises it by 10 dB, and a hundredfold increase raises it by 20 dB. This means that even a few decibels of noise reduction through barriers can make a significant difference.
WHAT IS ACOUSTIC INSULATION?
Acoustic insulation refers to the difference between the noise level outside and inside a room when a specific barrier is used. The applicable standards define the required values for different barriers and specify the indicators used to describe their insulation performance.
The primary indicator is Rw – the weighted sound reduction index. Two additional adaptation indicators adjust this value depending on the type of noise:
Ctr – used for low and mid-frequency sounds.
C – used for mid and high-frequency sounds.
The total insulation performance for different types of noise is calculated by combining Rw with these adaptation indicators.
Examples of low and mid-frequency noises include conversations, music, radio, TV, children playing, railway traffic at medium and high speeds, highway traffic, and nearby jet aircraft. The RA1 index describes the insulation performance against these noises (Rw minus C, reduced by 1-3 dB).
For noise sources such as urban traffic, slow-moving trains (under 80 km/h), nightclubs, and distant jet aircraft, the RA2 index applies (Rw minus Ctr, reduced by 4-8 dB).
HOW TO SOUNDPROOF GLASS?
Soundproof windows are more expensive and custom-made. In buildings exposed to high noise levels—such as those near airports, railway tracks, highways, or city centers—they significantly reduce external noise, though they cannot eliminate it entirely.
By using one or a combination of methods to improve the acoustic insulation of insulating glass units in windows, their noise reduction capability can be increased to 46-50 dB. However, the total noise protection of a window is slightly lower, as installation methods and frames can reduce effectiveness by a few decibels. Still, a window that reduces noise by around 40 dB makes a noticeable difference. (Keep in mind that a 10 dB reduction is perceived as halving the noise level.)
It’s also worth noting that high-insulation glass can be used in roof windows. This not only protects interiors from external noise but also dampens the sound of rain or hail—a valuable feature for windows in bedrooms or children's rooms.