To ensure that sound can be reflected from the wall of the room and not be heard outside, a technique called sound insulation is used. Soundproofing insulation for sound insulating slabs helps prevent noise from penetrating outside the room. Typically, this characteristic directly depends on the thickness of the material - the wider the soundproofing barrier, the less likely it is to hear sound. Also, sound insulation is used in the construction of buildings and is measured in Dicibels. Normal sound insulation characteristics are from 52 to 60 dB. Soundproofing materials reflect sound, including brick, plasterboard, concrete and others.
Sound absorption
The main purpose of the above characteristic is to prevent sound from being reflected from the wall. In terms of their structure, soundproofing boards consist of fibers or cells. The noise absorption coefficient varies from 0 to 1. If it is zero, the sound is reflected into the room, and if there is one, the sound is completely absorbed by the material. Materials corresponding to a number of 0.5 and above have noise absorption characteristics. To be comfortable, a person should be in a room with a noise level of 25 dB, since with a lower coefficient he will feel oppressive silence, and with a higher coefficient he will complain of noise and headaches. A person can easily tolerate noise up to 60 dB, but higher volumes can have a detrimental effect on health. In order to protect yourself from noise, you can use soundproofing insulation, depending on what your goal is.
This material has its own degree of hardness:
solid material - created using granulated mineral water. This type of raw material includes vermiculite, perlite and pumice. The optimal absorption coefficient is 0.5 dB with a mass of 300 kg/m3;
semi-rigid material - mineral wool slabs with a cell-shaped structure. Sound absorption coefficient from 0.5 to 0.7 dB with a mass of 130 kg/m3;
soft material - created on the basis of cotton wool or felt. Sound absorption coefficient from 0.5 to 0.95 with a mass of 70 kg/m3.
When constructing private houses, soundproofing devices of the last specified parameter are usually used. Also you should choose a soundproofing one with necessary properties depending on the nature of the noise produced.
Types of noise produced:
airborne, emitted from televisions, receivers, animals;
percussion, emitted when walking, repairing, drilling;
structural, appearing in the presence of connected load-bearing structures building.
To cope with impact noise, soundproofing soft materials with a cell structure are usually used. Soundproofing fibrous materials are used against the air, and special gaskets that protect the joints of structures are used against the structural.
Values of sound absorption and noise reduction coefficients
Table No. 1 shows the values of the weighted average sound absorption coefficients (aw) and NRC noise reduction coefficients for the panel of brands under consideration.
Table No. 1
| Manufacturer | Soundproofing board series | aw | NRC |
| USG | Sonaton GF | 0,7 | 0,7 |
| Sonaton Premier | 0,85 | 0,9 | |
| Sonaton TF | 0,7 | 0,7 | |
| OWA | Finetta | 0,7 | 0,65 |
| Cosmos | 0,7 | 0,65 | |
| Futura | 0,7 | 0,75 | |
| Harmony | 0,75 | 0,75 | |
| AMF | Feinstratos | 0,6 | 0,55 |
| Laguna | 0,6 | 0,6 | |
| Feinfresco | 0,6 | 0,65 | |
| Star | 0,65 | 0,55 | |
| Armstrong | Sabbia | 0,65 | 0,65 |
| Ultima | 0,65 | 0,7 | |
| Frequency | 0,65 | 0,7 | |
| Illbruck | Whiteline | 0,75 | - |
| Pyramide | 0,6-0,9 | - | |
| Acoustic panel | 0,75-0,85 | - | |
| Knauf | Knauf-Acoustics type A, B, C, D, E | 0,3-0,4 | - |
| using glass/basalt fiber | 0,7-0,8 | - | |
| Gustafs | BF-panel (16 types of perforation) using glass/basalt fiber | 0,3-0,9 | - |
| Ecophon | Focus | 0,9< | 0,9 |
| Gedina | 0,9 | 0,9 | |
| Harmony | 0,85 | 0,8 | |
| Pop | 0,5 | 0,45 | |
| Wall Panel | 0,95 | 0,95 | |
| Rockfon | Sonar | 0,8 | 0,8 |
| Koral | 0.9 | 0.85 | |
| Alaska | 0.85 | 0.8 | |
| Samson | 1 | 0.95 | |
| Parafon | Exclusive | 0,95 | 0,95 |
| Classic | 0,95 | 0,95 | |
| Basic | 0,95 | 0,95 | |
| Wall Panel | 0,9 | 0,9 |
Analyzing the indicators in table No. 1, we note that the base contains mineral fibers characterized by similar sound absorption coefficients, the difference is within 10%. A product made from a material based on perforated gypsum is somewhat inferior in sound-absorbing properties to mineral fiber slabs. Soundproofing gypsum insulation can be enhanced by adding an additional insulating layer. During construction public buildings and finishing, strict standards are applied that are designed to ensure the safety of people in the premises. Fire and environmental safety create a tight framework for soundproofing panels, compliance with which is strictly regulated. In addition, the materials used for finishing must be durable, easy to use, have moisture-resistant qualities and have an attractive appearance.
Characteristics of acoustic products
Soundproofing materials from different manufacturers (summary table No. 2).
Table No. 2
|
Manufacturer/ product |
Density, kg/m3 | Temperature resistance, °C | Moisture resistance,% | Environmental friendliness |
| Illbruck/ Pyramide | 9,5-11 | up to 150 | - | safe |
| Ecophon/Gedina | 125-200 | up to 800 | 95 | safe |
| Ecophon/Focus | 125-200 | up to 800 | 95 | safe |
| Rockfon/Koral | 70-90 | up to 1100 | 95-100 | safe |
| Rockfon/Sonar | 200-280 | up to 1100 | 95-100 | safe |
| Parafon/Exlusive | 140-280 | up to 1100 | 95 | safe |
| Parafon/Classic | 100-140 | up to 1100 | 95 | safe |
Continuation of table No. 2
The soundproofing materials in this table No. 2 reflect the difference in performance. For example, foamed acoustic material based on melamine resin from Illbruck (Germany) has a low density and also rather low resistance to temperature changes. This suggests that it is necessary to take into account that the scope of application of such materials is very limited. Soundproofing materials and their density produced by Ecophon, Parafon and Rockfon are approximately the same level. The similarity of this parameter is ensured by the similar insulating structure of this material. Soundproofing boards of these brands have a density that is much higher than that of foam materials, and in relation to the density of gypsum panels (900-1200 kg/m3) it is lower. At the same time, products for sound insulation made from basalt fiber are characterized by fire safety, moisture resistance, environmental friendliness, thermal insulation and durability. This is quite a big advantage, allowing you to use them during installation suspended ceilings and as acoustic soundproofing wall panels for all types of premises: from apartments and offices, to cinemas and recording studios.
Soundproofing products in cinema premises perform the main task of maintaining sound conditions throughout the entire area. Materials should not allow this sound to spread beyond its boundaries.
Such sound insulation is carried out immediately by a set of actions. For example, for such work several types of materials are used that absorb sound. Such materials cover not only the walls and ceilings, but also the floor.
Such coverings are called carpet. It is necessary when decorating rooms, because it has a very beautiful and flat surface with short pile. This makes the carpet very similar to a carpet or carpet.
Also for cinema owners, soundproofing products are provided in huge selection color range. And there are not only standard colors presented, but also various shades that will suit almost any interior and room design. Owners can choose not only the quality that suits them, but also choose a color whose relationship to the furniture upholstery will be ideal.
Our company can offer its clients:
Soundproofing material and its technological properties?
In the cinema you need to create using additional materials unprecedented acoustic perfect sound insulation. This is necessary so that all vibration, all hum and all sounds must remain in one isolated room. Carpet, in turn, copes well with the task entrusted to him. It not only easily reduces sound conductivity, but also does not affect acoustics at all. This material is very easy to install as it is very pliable and very easy to cut and stretch. Without any problems, it can also be fixed to ceilings, thereby forming a perfectly smooth surface.
The only condition for installing carpet is the room temperature. All sound insulation must take place in a room whose temperature should not fall below 16 degrees. Otherwise, the carpet completely stops stretching, which does not allow the panels to be joined on uneven areas.
In such cases, use makes it possible to minimize noise and ensure comfortable acoustic conditions for rooms adjacent to the cinema hall.
Do not forget that the soundproofing of the hall makes it possible to enjoy the film, completely immersing yourself in its atmosphere, without being distracted by loud noise from the corridor or the neighboring cinema hall.
IN modern world To fully implement the sound insulation process, materials are used that sufficiently have noise-reflecting or noise-absorbing properties.
Priority directions for soundproofing a movie theater or bowling alley.
- The most important task is to isolate the sounds of a cinema or bowling alley from nearby rooms. Therefore, sound insulation is necessary not only for walls, but also for ceilings and floors. This will prevent the sound from spreading further. For a cinema, it is mandatory to soundproof all rooms in which the film is shown.
- An important task is to ensure acoustic comfort directly in the hall in which a movie is being watched or a game of bowling is taking place. This requires sound insulation as well technical equipment: air conditioning, fans, refrigeration machines And so on.
- Do not forget that sound insulation should not interfere with the comfortable viewing of movies. The actors' speech should be easy to understand and audible. In a cinema hall, sound needs to travel evenly and efficiently throughout the hall in order to reach all rows at the same time. In a bowling alley, such subtleties are not provided.
As the quality of housing improves, when the issue of the number of square meters has ceased to be the only determining factor, the problem of soundproofing residential premises is becoming increasingly relevant. However, due to the fact that this question quite specific, i.e. in the theory of acoustics there are a lot of implicit features and “illogical” conclusions from the point of view of common sense; a large number of myths and misconceptions have arisen and become established in this area.
This leads to the fact that large quantity people have formed a stable stereotype about what materials, if necessary, can solve all the problems of insufficient sound insulation. However practical use Such materials will, at best, leave the situation without visible changes, at worst, it will lead to an increase in noise in the room. As a first example:
The myth about the soundproofing properties of cork
What cork covering- a good sound insulator, almost everyone believes. Statements of this kind can be found in many construction forums. And the “technology” of application is “developed” down to the smallest detail. If you can hear your neighbor behind the wall, you need to cover the wall you share with your neighbor with cork; if the noise is coming from the ceiling, then the ceiling. And the resulting acoustic effect is amazing... by its absence! But what's the matter? After all, the seller showed data from acoustic tests, where the effect of sound insulation was indicated, and not a small effect - about 20 dB! Is it really a scam?!
Not really. The numbers are true. But the fact is that such figures were obtained not for “sound insulation in general”, but only for the so-called impact noise insulation. In addition, the indicated values are only valid when the cork covering is laid under concrete screed or parquet board at the neighbor's upstairs. Then you really hear your neighbor’s steps 20 dB quieter compared to if your neighbor didn’t have this pad under his feet. But for music or the sound of a neighbor’s voice, as well as for all other cases of using cork covering in other options, these “sound insulation” figures, unfortunately, have nothing to do with it. The effect is not just barely noticeable, it is zero! Of course, cork is environmentally friendly and warm material, but it is not worth attributing all possible soundproofing properties to it.
All of the above also applies to polystyrene foam, polyethylene foam (PPE), polyurethane foam and other similar materials that have different trade marks starting with “peno-” and ending with “-fol”, “-fom” and “-lon”. Even with an increase in the thickness of these materials to 50 mm, their sound insulation properties (with the exception of impact noise insulation) leave much to be desired.
Another misconception, closely related to the first. Let's denote it as:
The myth of thin sound insulation
The basis for this misconception is the struggle to improve the acoustic comfort of the room along with the desire to preserve the original square meters. It is quite understandable to want to maintain the height of the ceiling and the area of the room, and also for standard apartments with a small footage and a low ceiling. According to statistical observations, the vast majority of people are willing to sacrifice “for sound insulation” by increasing the thickness of the wall and ceiling by no more than 10 - 20 mm. In addition to this, there is a requirement to obtain a hard front surface ready for painting or wallpapering.
Here all the same materials come to the rescue: cork, PPE, polyurethane foam up to 10 mm thick. Thermal and sound insulation is added to them as a separate line. But in this case, these materials are covered with a layer of plasterboard, which acts as a rigid wall, ready for finishing.
Since the acoustic properties of cork and PPE for sound insulation of walls and ceilings were discussed above, we will focus on thermal and sound insulation.
Termozvukoisol (TZI) - roll material, where it is used as a shell (like a duvet cover) polymer material"Lutrasil", and super-thin fiberglass fibers are used as padding (blanket). The thickness of this material ranges from 5-8 mm. I don’t presume to discuss the thermal insulation qualities of TZI, but as for sound insulation:
Firstly, TZI is not a sound-proofing material, but a sound-absorbing material. Thus, we cannot talk about its own sound insulation. We can only talk about sound insulation of a structure in which it is used as a filler.
Secondly, the sound insulation of such a design largely depends on the thickness of the sound-absorbing material located inside. The thickness of the TZI, at which this material will be effective in a soundproofing structure, must be at least 40 - 50 mm. And this is 5 - 7 layers. With a layer thickness of 8 mm, the acoustic effect of this material VERY SMALL. As, indeed, any other materials the same thickness. There's nothing you can do about it - the law of acoustics!
In quality indeed effective material For additional sound insulation of walls and ceilings, ZIPS panels can be recommended. For example, ZIPS-Vector panels with a structure thickness of 53 mm increase noise insulation by 9-11 dB, and the latest ZIPS-III-Ultra with the same thickness - by 11-13 dB. The panels are patented and currently have no analogues in the world.
Thus, with a total thickness of the additional sound insulation structure of 20 - 30 mm (including a layer of plasterboard), one should not expect any noticeable increase in sound insulation.
In addition to these, perhaps the most common misconceptions, there are others, less known, but no less significant. Therefore, in matters of ensuring the required noise insulation of premises, it is best to immediately contact specialists. Sometimes one glance is enough for an acoustics professional to immediately assess the ineffectiveness of the proposed measures or materials used. But the most unpleasant thing is to waste time, effort and money, and not feel the results of your work.
Acoustic principles are often not quite correctly interpreted and, as a result, incorrectly applied in practice.
Much of what should be considered knowledge and experience in this field often turns out to be incompetence. The traditional approach of most builders to solving problems of sound insulation and correction of room acoustics is based on practice and experience, which often limit or even reduce the overall acoustic effect. Successful acoustic projects tend to be free of misconceptions and pseudoscientific conclusions, and their content is aimed at ensuring that the money and effort invested will produce beneficial and predictable results.
Listed below are some of the most common acoustic myths that we constantly encounter when communicating with our clients.
Myth #1: Soundproofing and sound absorption are the same thing
Data: Sound absorption is a reduction in the energy of a reflected sound wave when interacting with an obstacle, for example a wall, partition, floor, ceiling. It is carried out by dissipating energy, converting it into heat, and exciting vibrations. Sound absorption is assessed using the dimensionless sound absorption coefficient αw in the frequency range 125-4000 Hz. This coefficient can take a value from 0 to 1 (the closer to 1, the correspondingly higher the sound absorption). With the help of sound-absorbing materials, hearing conditions inside the room are improved.
Sound insulation - reducing the sound level when sound passes through the fence from one room to another. The effectiveness of sound insulation is assessed by the airborne noise insulation index Rw (averaged in the range of the most typical frequencies for housing - from 100 to 3000 Hz), and of interfloor ceilings also by the index of the reduced level of impact noise under the ceiling Lnw. The more Rw and the less Lnw, the higher the sound insulation. Both quantities are measured in dB (decibel).
Advice: To increase sound insulation, it is recommended to use the most massive and thick enclosing structures. Finishing a room with sound-absorbing materials alone is ineffective and does not lead to a significant increase in sound insulation between rooms.
Myth No. 2: The higher the value of the airborne noise insulation index Rw, the higher the sound insulation of the fence
Data: The airborne sound insulation index Rw is an integral characteristic used only for the frequency range 100-3000 Hz and designed to assess noise of domestic origin ( Speaking, radio, TV). The higher the Rw value, the higher the sound insulation exactly this type.
In the process of developing the methodology for calculating the Rw index, the emergence of home theaters and noisy noise in modern residential buildings was not taken into account. engineering equipment(fans, air conditioners, pumps, etc.).
It is possible that lightweight frame a gypsum plasterboard partition has an Rw index higher than that of a brick wall of the same thickness. In this case, the frame partition isolates the sounds of a voice, a running TV, a ringing phone or an alarm clock much better, but a brick wall will reduce the sound of a home theater subwoofer more effectively.
Advice: Before erecting partitions in a room, analyze the frequency characteristics of existing or potential noise sources. When choosing design options for partitions, we recommend comparing their sound insulation in third-octave frequency bands, rather than Rw indices. To soundproof low-frequency noise sources (home theater, mechanical equipment), it is recommended to use enclosing structures made of dense solid materials.
Myth No. 3: Noisy engineering equipment can be located in any part of the building, because it can always be soundproofed with special materials
Data: Correct location noise engineering equipment is a task of paramount importance when developing an architectural and planning solution for a building and measures to create an acoustically comfortable environment. Soundproofing structures and vibration-proofing materials can be very expensive. Despite this, the use of soundproofing technologies cannot always reduce the acoustic impact of engineering equipment to standard values throughout the entire audio frequency range.
Advice: Noisy engineering equipment must be located away from the protected premises. Many vibration-isolating materials and technologies have limitations in their effectiveness depending on the combination of weight and size characteristics of the equipment and building structures. Many types of engineering equipment have pronounced low-frequency characteristics that are difficult to isolate.
Myth No. 4: Windows with double-glazed windows (3 panes) have higher sound insulation characteristics compared to windows with single-chamber double-glazed windows (2 panes)
Data: Due to the acoustic connection between the glasses and the occurrence of resonance phenomena in thin air gaps (usually they are 8-10 mm), double-glazed windows, as a rule, do not provide significant sound insulation from external noise compared to single-chamber double-glazed windows of the same width and total glass thickness. With the same thickness of double-glazed windows and the total thickness of the glass in them, a single-chamber double-glazed window will always have a higher value of the airborne noise insulation index Rw compared to a double-chamber one.
Advice: To increase the sound insulation of a window, it is recommended to use double-glazed windows of the maximum possible width (at least 36 mm), consisting of two massive glasses, preferably of different thicknesses (for example, 6 and 8 mm) and the widest possible distance strip. If a two-chamber double-glazed window is used, then it is recommended to use glass of different thicknesses and air gaps different widths. The profile system must provide a three-circuit seal of the sash around the perimeter of the window. In real conditions, the quality of the sash affects the sound insulation of the window even more than the formula of the double-glazed window. It must be taken into account that sound insulation is a frequency-dependent characteristic. Sometimes a glass unit with a higher Rw index value may be less efficient compared to a glass unit with a lower Rw index value in some frequency ranges.
Myth No. 5: The use of mineral wool mats in frame partitions is sufficient to ensure high sound insulation between rooms
Data: Mineral wool is not a soundproofing material; it can only be one of the elements of a soundproofing structure. For example, special sound-absorbing boards made of acoustic mineral wool can increase the sound insulation of plasterboard partitions, depending on their design, by 5-8 dB. On the other hand, covering a single-layer frame partition with a second layer of plasterboard can increase its sound insulation by 5-6 dB.
However, it must be remembered that the use of arbitrary insulation materials in soundproofing structures leads to a much smaller effect or does not have any effect on sound insulation at all.
Advice: To increase the sound insulation of enclosing structures, it is strongly recommended to use special slabs made of acoustic mineral wool due to its high sound absorption rates. But acoustic mineral wool must be used in combination with soundproofing methods, such as the construction of massive and/or acoustically decoupled enclosing structures, the use of special soundproofing fasteners, etc.
Myth No. 6: Sound insulation between two rooms can always be increased by erecting a partition with a high sound insulation index value
Data: Sound propagates from one room to another not only through the dividing partition, but also through all adjacent building structures and engineering communications(partitions, ceiling, floor, windows, doors, air ducts, water supply, heating and sewerage pipelines). This phenomenon is called indirect sound transmission. All building elements require soundproofing measures. For example, if you build a partition with a sound insulation index of Rw = 60 dB, and then install a door without a threshold in it, then the total sound insulation of the fence will practically be determined by the sound insulation of the door and will be no more than Rw = 20-25 dB. The same thing will happen if you connect both isolated rooms with a common one. ventilation duct, laid through a soundproof partition.
Advice: When constructing building structures, it is necessary to ensure a “balance” between their sound insulation properties so that each of the sound propagation channels has approximately the same impact on the total sound insulation. Special attention attention should be paid to the ventilation system, windows and doors.
Myth No. 7: Multilayer frame partitions have higher sound insulation characteristics compared to conventional 2-layer ones
Data: Intuitively, it seems that the more alternating layers of plasterboard and mineral wool, the higher the sound insulation of the fence. In fact, the sound insulation of frame partitions depends not only on the mass of the cladding and on the thickness of the air gap between them.
Various designs of frame partitions are shown in Fig. 1 and are arranged in ascending order soundproofing ability. As an initial design, consider a partition with double gypsum board cladding on both sides.
If we redistribute the layers of drywall in the original partition, making them alternate, we will divide the existing air gap into several thinner segments. Reducing the air gaps leads to an increase in the resonant frequency of the structure, which significantly reduces sound insulation, especially at low frequencies.
With the same number of gypsum board sheets, a partition with one air gap has the greatest sound insulation.
Thus, applying the right technical solution when designing soundproof partitions and the optimal combination of sound-absorbing and general construction materials has a much greater impact on the final soundproofing result than a simple choice of special acoustic materials.
Advice: To increase the sound insulation of frame partitions, it is recommended to use structures on independent frames, double or even triple gypsum board cladding, fill inner space frames with special sound-absorbing material, use elastic gaskets between the guide profiles and building structures, carefully seal the joints.
It is not recommended to use multilayer structures with alternating dense and elastic layers.
Myth No. 8: Polystyrene foam is an effective soundproofing and sound-absorbing material.
Fact A: Polystyrene foam is available in sheets of various thicknesses and bulk densities. Various manufacturers They call their products differently, but the essence does not change - it is expanded polystyrene. This is wonderful heat insulating material, but it has nothing to do with soundproofing airborne noise. The only design in which the use of polystyrene foam can have a positive effect on noise reduction is when it is laid under a screed in a floating floor structure. And even then this applies only to reducing impact noise. At the same time, the effectiveness of a layer of foam plastic 40-50 mm thick under the screed does not exceed the effectiveness of most cushioning soundproofing materials with a thickness of only 3-5 mm. The overwhelming majority of builders recommend gluing sheets of foam plastic to walls or ceilings and then plastering them to increase sound insulation. In fact, such a “soundproofing structure” will not increase, and in most cases even reduce (!!!) the sound insulation of the fence. The point is that the lining massive wall or covering with a layer of plasterboard or plaster using an acoustically rigid material, such as polystyrene foam, leads to deterioration of the sound insulation of such a two-layer structure. This is due to resonant phenomena in the mid-frequency region. For example, if such cladding is mounted on both sides of a heavy wall (Fig. 3), then the reduction in sound insulation can be catastrophic! In this case, a simple oscillatory system is obtained (Fig. 2) “mass m1-spring-mass m2-spring-mass m1”, where: mass m1 - plaster layer, mass m2 - concrete wall, the spring is a layer of foam.
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Rice. 2 ÷ 4 Deterioration of airborne noise insulation by the wall when installing additional cladding (plaster) on an elastic layer (foam plastic).
a - without additional cladding (R’w=53 dB);
b - with additional cladding (R’w=42 dB).
Like any oscillatory system, this design has a resonant frequency Fo. Depending on the thickness of the foam and plaster, the resonant frequency of this structure will be in the frequency range 200÷500 Hz, i.e. falls into the middle of the speech range. Near the resonant frequency, a dip in sound insulation will be observed (Fig. 4), which can reach a value of 10-15 dB!
It should be noted that the same disastrous result can be achieved by using materials such as polyethylene foam, polypropylene foam, some types of hard polyurethanes, sheet cork and soft fiberboard instead of polystyrene foam in such a structure, and instead of plaster plasterboard boards on glue, sheets of plywood, chipboard, OSB.
Fact B: In order for a material to absorb sound energy well, it must be porous or fibrous, i.e. ventilated. Expanded polystyrene is a windproof material with a closed cell structure (with air bubbles inside). A layer of foam plastic mounted on a hard surface of a wall or ceiling has a vanishingly low sound absorption coefficient.
Advice: When installing additional soundproofing linings, it is recommended to use acoustically soft sound-absorbing materials, for example, based on thin basalt fiber, as a damping layer. It is important to use special sound-absorbing materials, and not random insulation.
And finally, probably the most important misconception, the exposure of which follows from all the facts given above:
Myth No. 9: You can soundproof a room from airborne noise by gluing or attaching thin but “effective” soundproofing materials to the surface of the walls and ceiling
Data: The main factor that exposes this myth is the presence of the soundproofing problem itself. If such thin soundproofing materials existed in nature, then the problem of noise protection would be solved at the design stage of buildings and structures and would come down only to the choice of appearance and price of such materials.
It was said above that in order to isolate airborne noise, it is necessary to use sound-insulating structures of the “mass-elasticity-mass” type, in which between the sound-reflecting layers there would be a layer of acoustically “soft” material, sufficiently thick and having high values of the sound absorption coefficient. It is impossible to fulfill all these requirements within the total thickness of the structure of 10-20 mm. Minimum thickness soundproofing cladding, the effect of which would be obvious and tangible, is at least 50 mm. In practice, claddings with a thickness of 75 mm or more are used. The higher the sound insulation more depth frame.
Sometimes “experts” cite the example of soundproofing technology for car bodies using thin materials. In this case, a completely different noise insulation mechanism works - vibration damping, effective only for thin plates (in the case of a car - metal). The vibration damping material must be viscoelastic, have high internal losses and have a thickness greater than that of the insulated plate. Indeed, in fact, although car sound insulation is only 5-10 mm thick, it is 5-10 times thicker than the metal itself from which the car body is made. If we imagine an inter-apartment wall as an insulated plate, then it becomes obvious that the “automotive” method of vibration damping can be used to soundproof a massive and thick brick wall it won't work.
Advice: Carrying out soundproofing work in any case requires certain losses usable area and room height. It is recommended to contact an acoustics specialist at the design stage in order to minimize these losses and choose the cheapest and most effective option soundproofing your room.
Conclusion
There are many more misconceptions in the practice of building acoustics than described above. The examples given will help you avoid some serious mistakes during the production of construction or repair work in your apartment, house, recording studio or home theater. These examples serve to illustrate that you should not unconditionally believe repair articles from glossy magazines or the words of an “experienced” builder - “...And we always do it this way...”, which are not always based on scientific acoustic principles.
A reliable guarantee of the correct implementation of a set of soundproofing measures that ensure maximum acoustic effect can be provided by competently compiled recommendations by an acoustic engineer for soundproofing walls, floors and ceilings.
Andrey Smirnov, 2008
Bibliography
SNiP II-12-77 “Noise Protection” / M.: “Stroyizdat”, 1978.
“Manual for MGSN 2.04-97. Design of sound insulation of enclosing structures of residential and public buildings”/- M.: State Unitary Enterprise “NIAC”, 1998.
“Handbook for protection from noise and vibration of residential and public buildings” / ed. IN AND. Zaborov. - Kyiv: ed. "Budevelnik", 1989.
"Designer's Handbook. Noise protection” / ed. Yudina E.Ya. - M.: “Stroyizdat”, 1974.
“Guide to the calculation and design of sound insulation of building envelopes” / NIISF Gosstroy USSR. - M.: Stroyizdat, 1983.
“Noise reduction in buildings and residential areas” / ed. G.L. Osipova / M.: Stroyizdat, 1987.
Today you can purchase soundproofing materials in almost any hardware store. They are presented on the market in a huge variety from foreign and domestic manufacturers. And those who decide to purchase these materials for the first time face a rather big problem. the right choice. It’s difficult to understand all this, and you can’t do it without the help of a specialist. Therefore, our article is to help those who want to figure it out.
So where do you start? Firstly, it should be noted that the variety of modern soundproofing materials has thrown aside the old methods of soundproofing. These include the use of insulation different types. Practice has shown that mineral wool in slabs was most often used for these purposes. It performed the functions of both heat and sound insulation.
Secondly, the process of laying sound insulators has become much simpler. And this is one of the important selection criteria, because nowadays consumers are trying to do some things with their own hands. construction works to save the budget allocated for repairs. AND modern materials This can be done for soundproofing.
The third selection criterion is the cost of materials. Although it should be noted that in this case the price range is not very wide, so it is best to choose according to other criteria.
Classification of soundproofing materials
Soundproofing materials are divided into three main groups:
- Sound-absorbing.
- Soundproof against shock vibrations.
- Soundproof against air vibrations.
What is the difference between these groups? Let's start with the fact that sound is energy. When it falls on the enclosing structure, it is partially reflected from it, partially absorbed by it and partially passes through it. So, those representatives of the group that mainly absorb sound energy are called noise-absorbing materials or sound-absorbing materials. Those that mainly reflect sound waves are called soundproofing.
Sound-absorbing
Sound-absorbing materials
There is such a thing in acoustics as a sound field. Essentially, this is the area of propagation of sound waves from the source. So in the field there are two types of sound - direct from the source and reflected from various items. So the latter are distorted, their intensity is increased, and the sound character goes into a worse range. Noise-absorbing materials reduce the energy of the reflected signal to a minimum. That is, the sound field is stabilized.
Important. Materials of this type must therefore be porous. And the higher this indicator, the better. And if, in order to retain heat, it is necessary to use materials with closed pores, then in sound insulation, on the contrary, they must be open (communicating). Plus, heat is retained better if there are pores big size, and sound is absorbed better if they are small.
Why is this happening? The point is that the wave passing through the air located in the pores soundproofing material, causes this air to vibrate. Small pores create better resistance to them than large pores. This is the first. Secondly, the noise flow is inhibited inside the material. The friction of air against the pore walls converts mechanical energy into heat. That is, the intensity and power of noise decreases.
There is another indicator of soundproofing materials - elasticity. If the soundproofing structure has a flexible frame, then this is another noise reduction barrier. The waves hitting it do not transmit vibrations to the entire material. This means the noise level is reduced.
Absorption coefficient
Absorption coefficient
Materials for sound insulation of the absorbing type are determined by efficiency, or more precisely, by absorption coefficient. The coefficient itself is the ratio of the absorbed energy to the energy of the entire incident sound on the material. This indicator is based on one square meter open window. This is "1". All soundproofing materials with a coefficient below “0.4” are sound-absorbing. In this case, the condition is set that the noise frequency should not exceed 1000 Hz.
There is another value - noise level. Essentially, this is the time during which the reflected wave sounds. This indicator is otherwise called reverberation time. For example, we can give the following test. If you create a signal in an empty room with bare walls, the reverberation time will be about 8 seconds. If soundproofing material is laid on the walls, this indicator will be reduced to one second.
Soundproofing against shock sound vibrations
This type of soundproofing materials is a porous product with a low elasticity coefficient. Essentially, these are noise-insulating cushioning materials that also retain heat well.
But their main purpose is to prevent shock vibrations. Therefore, their production is based on the technology of creating a structure in which the speed of sound propagation was the lowest. Everyone knows that the denser the material, the faster sound travels through it. Eg:
- In metal, the propagation speed is 5050 m/s.
- In concrete – 4150 m/s.
- In a tree – 1550 m/s.
- In porous type rubber, only 30 m/s.
Therefore, this type of soundproofing gasket material is mainly used as gaskets. They are most often laid between finishing structures and load-bearing elements buildings, between the building elements themselves, between floating floors and walls.
Soundproof against air waves
Firstly, it must be said that the house structures themselves can act as sound insulators. The greater the density of the product, the greater its mass, the greater the soundproofing properties they have. True, all this increases the cost of the building, so experts recommend installing multi-layer structures with air gaps. It is the gap that must be filled with sound-absorbing insulation, that is, filled or installed with porous materials. By the way, such a soundproofing system perfectly retains heat.
Advice. The optimal option for a soundproofing design is a system consisting of different materials, which have different densities, rigidity, and tightness.
Other classification criteria
By appearance:
- Piece - slabs, panels, mats, rolls and so on.
- Bulk.
By porosity:
- Cellular.
- Fibrous.
- Combined.
Soundproofing products must be non-flammable, with low water absorption, low hygroscopicity, and bioresistant. The thing is that sound insulation is practically a finish installed from the inside of the premises. So she is also subject to quite stringent requirements.
All noise can be classified into three categories: airborne, impact and structural. The most common type, of course, is airborne noise - this includes the sounds of passing vehicles, the hum of equipment, and the sounds made by animals and people.The ability of a material to protect from noise will tell you the index of sound insulation – Rw.
Impact noise, as the name suggests, occurs when shocks occur, such as when hammering nails or moving furniture. Finally, structural noise is the sounds of nature that penetrate the structural elements of a home.
The key characteristics of soundproofing material are sound insulation and sound absorption. It should reflect or absorb sound, preventing it from entering the room.
From the point of view of acoustic engineers, there are no soundproofing materials in nature - only special designs in which the structure is extremely important. Often, builders use multilayer systems in which sheets of dense plasterboard alternate with layers of porous materials, such as mineral wool. But, unfortunately, they reduce living space and are quite expensive.
The secret of effective sound-proofing – a combination of special design and material.
Review of popular soundproofing materials
Modern technologies make it possible to use simpler and more cost-effective materials that provide insulation from external and internal noise. Thus, ZIPS sandwich panels have proven themselves well on the market. They are a combination of dense gypsum fiber and soft glass wool layers. Their thickness varies from 40 to 130 mm, and Rw is 10 dB.More thin material are heat and soundproofing boards ISOPLAAT. Their thickness does not exceed 25 mm, and their sound insulation index is twice as high as that of ZIPS - 23 dB. In addition, ISOPLAAT is made from environmentally friendly fibers coniferous trees. The boards are mounted using glue and “breathe” well.
The thinnest panels are EcoZvukoIzol and Kraft - 12 mm and 13 mm, respectively. The first ones are made of a seven-layer cardboard profile with the addition quartz sand, the second - from wood fiber boards. Both are easily attached with ordinary glue. The sound insulation index of both is approximately 23 dB.
Finally, it is worth warning about the most common misconceptions. There is an opinion that materials such as cork, PPE, polyurethane foam do a good job of soundproofing and at the same time, due to their small thickness, help save square meters. In fact, this is not entirely true - they only absorb impact noise, but do not insulate at all from airborne noise.