The acoustic project

One of the fundamental aspects aimed at ensuring individual well-being within buildings is represented by theenvironmental acoustics. In construction, correct acoustic design aims to contain the noise generated by external and internal sources with respect to the home environment. The multiple soundproofing solutions concern the structure of the building but also everything that contributes to characterizing it from the point of view of furnishings and accessories. As far as the Italian territory is concerned, the standard UNI 11367 designates a subdivision of buildings according to the acoustic class to which they belong. This classification is useful to ensure more correct design in terms of acoustic comfort.

To follow one explanatory guide on the fundamental principles of acoustic design.

Noise pollution and measures to minimize it

THEnoise pollution It is an element that must be evaluated from the early stages of the design process because, in addition to being a cause of disturbance, it represents a problem that affects the health of the individual. In fact, many studies have shown how annoying noises generate problems related to stress, sleep and hypertension. For this reason, it is necessary to act appropriately both on the sources of noise and on the acoustic insulation of the building.

Noise can be produced by numerous sources outside or inside the building. Furthermore, it is important to point out that each type of building is different in this respect both for its intrinsic characteristics and for the intended use that distinguishes it. In the first case, these are sounds coming from the context, more intense within the urban setting: car horns, traffic, trams, construction sites, presence of large roads. As regards the noises present inside the housing unit, the most common are those coming from conversations, impacts, systems such as washing machines, dishwashers, boilers, ventilation systems and taps. Even the presence of elevators and freight elevators in the stairwell of buildings can represent a source of unpleasant noise.

Depending on the type of noise and the source that generates it, it will be a good idea to study the most suitable solution to best attenuate the disturbance for the human ear. In this regard, it is necessary to distinguish between sound absorption e sound insulation, concepts often confused with each other. The first is aimed at counteracting the sound that is reflected within a single environment, through the insertion of fibrous materials that will form walls and false ceilings. In fact, these materials have the ability to assimilate the sound and prevent it from spreading within the environment. In other words, it is a question of containing internal reverberation and for this reason sound-absorbing solutions are particularly suitable for buildings intended to accommodate large flows of people: offices, recording studios, theaters, bars and restaurants. Among the most common fibers are mineral, natural and synthetic ones: they range respectively from rock wool, to cork, to expanded polyurethane.

It is important to point out that optimal acoustic insulation often requires the co-presence of sound-absorbing and sound-insulating solutions. The latter represent the most suitable measure to contain the transmission of sound between multiple adjacent environments and between the outside and the inside. In this case, the material is considered a real barrier that blocks the entry of sound and reflects it into the environment in which the source that generates it is located. To intervene in this way, we usually proceed with solutions that combine wood fiber with rigid sound-absorbing panels.

UNI 11367: Italian legislation on acoustics

As regards noise pollution, Italian legislation began to make its way around the 90s, when, thanks to the introduction of specific decrees, design sensitivity increased in terms of noise containment in buildings. Some “limit thresholds” were thus defined within which it was necessary to stay in order to ensure the psycho-physical well-being of the user.
Given that the decibel represents the unit of measurement for quantifying sound intensity, the limit value of 50 dB is defined beyond which the sound is perceived as a disturbance for the human ear.

Precisely with regard to the limits that must be respected to avoid unpleasant noises, the Prime Ministerial Decree of 5 December 1997 was introduced which defines the passive acoustic requirements of buildings and is still currently in force. The decree establishes the values ​​that must be respected to obtain acceptable acoustic comfort with respect to noise between housing units, external sounds and those generated by systems and activities of various types.
These limits vary depending on the intended use of the property and for this reason, buildings are classified into categories:

• residential buildings - category A
• Category B offices
• hotels and similar - category C
• hospitals and nursing homes - category D
• schools-category E
• religious and recreational activities - category F
• commercial activities - category G

Furthermore, depending on the peculiarities of the property and the performance of each of its components, the standard UNI 11367 defines the acoustic class to which it belongs. It is necessary that, as a whole, the individual components comply with the defined performance standards, in acoustic terms. Acoustic design is mandatory in the case of new buildings or urban renovation projects. As regards new construction, at the end of the works it is always mandatory to verify compliance with the limit values ​​or, alternatively, to carry out acoustic testing.

Learn more about the acoustic design of a concert hall click here

Interventions for acoustic improvement

As anticipated, noise pollution is a problem that cannot be underestimated and for this reason it is necessary to study which is the most suitable intervention in order to counteract the intensity of the noises present in the confined environment. Among the most effective measures we can mention the increase in the thickness of floors and walls through the use of heavy materials (solid bricks) or the interposition of an acoustic insulator between two sections of light material (for example plasterboard). To counteract noises coming from outside it is a good idea to pay particular attention to the windows that must be installed correctly and sealed. It is then optimal to opt for double glazing and take care to insert a sound-absorbing material inside the shutter boxes since they are considered "weak" elements.

In the case of residences located on the top floor of the building, in a particularly busy area, an intervention at the roof level could prove essential. It will therefore be necessary to apply a thick layer of insulation in correspondence with the attic, combined with a dense material that will constitute the sound-absorbing panel. If you enjoy the beauty of a sloping ceiling with exposed wooden beams, in order not to sacrifice this aspect with the insertion of a false ceiling, it will be possible to intervene while maintaining the aesthetics and increasing the acoustic insulation. In this regard, we will proceed on the roof from the outside, replacing the plastic insulation, usually used with roofs of this type, with a wood fiber.

Example of a cork mat on which the parquet is laid

Another widely used solution for improving sound insulation inside buildings is represented by acoustic panels. The market offers many products: you can choose panels integrated into the walls, modules applicable to the floor, or those designed to create real false ceilings. In fact, depending on the source from which the noise comes, the panel can be inserted in the most appropriate position to minimize it. If the noise comes from above, sound-absorbing false ceilings will be optimal, for footfall noise it is necessary to opt for panels inserted into the floor, while if you want to attenuate the transmission of sounds from one room to another, you must place the modules between the two bordering walls.
Sound-absorbing panels are divided into resistive ones made of porous material, those that work by resonance and prevent the propagation of sound, and sound-diffusing ones capable of absorbing sounds at medium-high frequencies.

Additional measures within residential environments can help improve acoustic conditions and promote greater comfort. For example, it is advisable to place some carpets on the floor, choose soundproof appliances and even install washing machines and dryers on rubber mats capable of containing the vibrations that could occur when they are in operation.

Decorative sound-absorbing panels

The acoustics sector today is different from that of the past because the market is able to offer varied solutions to ensure the right comfort inside the environments, without sacrificing the aesthetic quality. In fact, if once the insertion of sound-absorbing panels was aimed only and exclusively at ensuring the right acoustic insulation to the environment, now it also fulfills a decorative function.

I decorative panels for interiors have received great approval and today they are produced in different shapes and colors, becoming an icon of style and an important furnishing component. An example of this are the picture panels created by the collaboration between graphic designers and manufacturers. They can become wall furnishings or real sculptures. In fact, since they are made of fabric, wood or vegetable fibers, they can be printed or subjected to numerous artistic processes.

Example of decorative sound-absorbing panels applied to walls. Photo on the right: planurban

Thanks to their versatility, sound-absorbing panels adapt well to any home style. For classic environments, wooden ones will be perfect, for those who want to add a touch of color, fabric ones are more suitable and, if equipped with lining, they allow you to replace textures and colors depending on the need. If you prefer a modern style, metal panels will be the most suitable because they are able to give an innovative and refined look to the environments. Finally, one of the latest innovations is represented by reflective panels: thanks to their glass surface, the panel will look like a real mirror hanging on the wall.

The sound-absorbing furniture

The need to include furniture that helps to counteract noise arises in the tertiary sector and specifically in office design. However, today, there is an increasingly widespread tendency to choose some furniture components that combine aesthetics and functionality in acoustic terms, even within residential spaces. In fact, thesound-absorbing furniture in addition to being optimal for ensuring greater comfort, it has the advantage of ensuring low costs and avoiding interventions on the structure of the building.

If the sound source is located in the neighbors' apartment, it would be a good idea to choose a sound-absorbing bookcase applied to the communicating wall, which, thanks to the materials used, will be able to dampen the noise.

Another example of widely used furniture is represented by the sound-absorbing fabric seatsand; these are solutions that use rock wool and glass wool, fibers usually used to manufacture the insulating layers of walls. Thanks to their versatility and flexibility of use, they can be moved to any environment depending on the need of the moment.
If, however, you wish to opt for a functional and at the same time very original complement, pendant lamps will be perfect, which, thanks to the multiple panels they are made of, guarantee optimal acoustic insulation comparable to that of false ceilings.

Today, thanks to the possibility of customizing interior design solutions, it will be possible to design tailor-made solutions, studied on the environment and able to satisfy acoustic and stylistic needs.
It is clear then how sometimes what starts out as a problem to be solved becomes a valid pretext to embellish one's residential environments!