Sound proof and barrier walls effectively cut down on noise pollution within or outside of a residential or commercial building. They are designed to be retrofitted to existing walls or can be used as new construction. Noise barriers are made out of several varieties of material, each with different levels of efficiency. There are several ways engineers incorporate noise mitigating strategies into building design. Sound proofing materials are made to either dampen sound by creating a “line of sight” barrier, reflect sound, or absorb sound.
Noise Pollution Health Effects
Noise pollution poses moderate health risks at certain levels. Levels over 65dB are considered “naturally unacceptable” and can lead to increased blood pressure, stress related illnesses, tinnitus, and even hearing loss. In communities where residential buildings and businesses are exposed to 65dB or more, noise mitigation strategies are highly encouraged. New construction in noisier areas, over 75dB, is required to have some sort of sound proofing, whether it be inside, outside, or both.
How Noise Mitigation Structures (Sound Proof Walls) Are Designed
The main concept when designing sound proof and sound barrier walls is to increase the distance that sound travels while also increasing the obstacles encountered within that distance. As sound travels, the sound waves lose both energy and density. Barriers placed at strategic points throughout that distance further impedes sound’s ability to travel and permeate walls. The second step in decreasing noise is to increase the mass of sound barriers. As mass increases, it requires more energy from sound waves to vibrate. Thus, increasing the mass will reduce the ability of the object to vibrate and enhance sound.
Lastly, objects that do not have the ability to vibrate at all are implemented. Softer objects that do not have hard, flat edges cannot produce vibrations. That’s why screaming into a pillow when you’re angry dampens the sound. Noise mitigation strategies take these three factors into account when designing sound barriers and soundproof walls. Sound barrier walls are often made of a sound damping material, which absorbs resonance and eliminates vibrations. Sound buffering materials can be any of the following:
- Porous absorbers. Materials like rubber foams and sponges are very effective at absorbing noise that is of a higher frequency. Depending on the thickness and porosity of the material, the barrier has varying levels of noise absorption.
- Resonant absorbers. Made of non-porous material, this option works by reflecting the sound. As the sound is reflected, it loses energy and intensity. This type of material works best at absorbing low frequency noises.
- Reflective noise barriers. These are typically used outdoors as highway embankments. They are made out of concrete or other solid forms of paneling and reflect noise upwards and away from surrounding communities. Because this type of barrier must be tall and wide to work properly, it is best used in expansive environments.
Commercial soundproofing usually encompasses a combination of sound dampeners, porous and non-porous, and flat, reflective sound walls. This is because commercial applications require a variety of sound frequencies to be addressed. In addition to soundproof barriers alongside highways and other roadways, engineers and architects have also taken to building designs that incorporate some degree of soundproofing. Many buildings are constructed with soundproofing materials and designed in a way that cuts down on noise pollutions. For example, materials such as concrete sound barriers may be built outside while several noise-absorbing features are implemented inside the walls.