Combating Noise With Noise Barriers


Noise is a mixture of sounds of various frequencies that is annoying to the individual and is currently considered an “invisible” pollutant in the world, generating great concern, especially in our neighborhoods near the urban area, where the number of vehicles, the desperation to move faster in traffic, the use of vehicle horns, or the use of music players constantly and at high volumes; these play an essential role in noise emissions, thus creating a significant impact on the health of the inhabitants. Moreover, the problems associated with hearing loss make a 40-year-old hear like a 60-year-old.

Besides, even at low levels, the generation of vehicular noise creates discomfort, disturbing sleep, so they can have insomnia, especially in more populated cities or those who live in a more significant area influx of people.

A specific relationship between noise and cardiovascular disorders has been documented; noise pollution could be affected. Noise exposure may increase the risk of AHT, angina pectoris, or acute myocardial infarction. This is due to the activation of nerve hormones, which will cause an increase in blood pressure or vasoconstriction, among others.

Noise can affect our organism physiologically because it can also increase stress or irritability (sounds of 80 – 90dB), which also influences mental activities such as concentrating (sounds with 70dB).

The most commonly used protective measure to minimize noise generated by transport infrastructure is noise barriers, as you can find at As they are called in the regulations, noise reduction devices improve comfort areas adjacent to roads and railways.

They are installed by interposing between the source of noise generated by the transport infrastructure and the receiver, the adjacent areas. The work by reflecting the noise to the road infrastructure or by absorbing part of the sound if these devices are made of materials that enable such a noise control mechanism.

Sound travels as a wave through media such as air, liquid, and plasma. In the air, the speed at which waves travel is determined by atmospheric conditions so that sound rate can vary depending on temperature. Acoustic screens are a concept developed in the 20th century when many scientists believed that aircraft drag caused by approaching sound speed made it impossible for any aircraft to reach or exceed the speed of sound without being destroyed. Since the sound rate is based on the medium’s temperature being moved, there is no constant speed at which the sound barrier is broken.

Acoustic screens or noise barriers reduce noise levels in residential, urban, and industrial areas by attenuating noise pollution from roads, railways, or industries.

We can find different types of acoustic screens. The most common are:

Metal acoustic screens are made of two metal sheets, usually steel, with a mineral wool core between them. The core’s density and the metal faces’ thickness vary significantly when the core is fully bonded to the steel.

There are different types of transparent screens; these can be made of PMMA methacrylate (the most commonly used material), polycarbonate or safety glass. Apart from covering, these materials help reduce noise and fulfill a visual function to interfere with the environment’s visibility minimally.

The mixed acoustic screens are generally formed by the mixture of a methacrylate acoustic screen (reflective material) in the upper part and an absorbent acoustic screen (metallic, concrete, wood, etc.) lower part.

The concrete screens consist of a reinforced concrete structure several centimeters thick, covered by two layers of mineralized wood conglomerate and cement. At its ends, there is a solid concrete band that allows the fitting of any steel beam with standard profiles.

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