Soundproofing a building is the limitation of noise that can disturb people living in the rooms of the building. Differently from the thermal insulation, which has the main purpose of energy saving, acoustic insulation does not bring direct economic advantages to the operating costs of the buildings, but concurs to a better confort of life and work experience. Today life is often stressful and noise inside buildings is often one of the main reasons of fights and complaints between neighbours and disputes between individuals. That’s why a soundproofed building can have a higher value on the market, compared to a building without insulation.
The acoustic insulation of a building is generally evaluated with the following parameters:
- Airborne sound insulation: evaluation of the sound reduction given by horizontal and vertical partitions separating two different dwellings, relative to noises generated and propagated through air.
- Facade acoustic insulation: evaluation of the noise coming from outside the building (traffic, airplanes, outside activities in general, building sites, …).
- Impact noise: evaluation of the structural noise generated for example by footsteps or furniture movement, transferred to the adjacent rooms vertically and horizontally.
- Noise from equipment: noise generated due to the use of toilets, showers, but also lifts, air treatment, …
Maximum or minimum performance are required by local laws, specific in every country.
The transmission loss R is a parameter that defines the airborne sound insulation for a partition, generally a wall or a floor separating two dwellings. It is a noise measured in deciBels on a wide frequency range spectrum (100 Hz – 3150 Hz), according to the formula:
R = L1 – L2 + 10Log S/A [dB]
(L1 is the noise level in the room where the noise is generated, L2 is the noise level in the room where the noise is received, S is the surface of the partition, A is the equivalent absorption surface of the receiving room). Since it is obtained from the difference of two noise levels, R has the meaning of “”insulation””, that means the higher is the R value and the better will be the insulation.
From the analysis in the whole spectrum a single rating index can be calculated and identified with the letter “”w””. When evaluated in laboratory, without flanking transmission, the rating index is called Rw, while when evaluated in site it is indicated with a single quote (for example R’w, …), because the flanking transmissions have an influence on the value. The reference standards for the measurement of the impact noise level in laboratory are the series ISO 10140, while the evaluation with the single rating index is done according to the ISO 717-1.
Ln = Li + 10Log A/Ao [dB]
(Li is sound pressure level in the receiving room, A is the equivalent absorption surface in the receiving room and Ao = 10 m² is the reference equivalente absorption surface). The structural noise source is called tapping machine and is made of five hammers that impact on the floor surface at a fixed rate. Since the perfromance is measured from a direct measurement of noise, the Ln value must be read inversely, that means the higher is the number and the worse will be the insulation; on the contrary, the lower the value of Ln, the better will be the insulation (the floor emits a lower noise).
From the analysis of noise in the whole spectrum a single rating index can be calculated and identified with the letter “”w””. When evaluated in laboratory, without flanking transmission, the rating index is called Lnw, while when evaluated in site it is indicated with a single quote (for example L’nw, L’nTw, …), because the flanking transmissions have an influence on the value. The reference standards for the measurement of the impact noise level in laboratory are the series ISO 10140, while the evaluation with the single rating index is done according to the ISO 717-2.
The acoustic insulation in buildings is evaluated through the determination in site of some requirements that depend exclusively on the characteristics of the structures and not on the outside environment. The major requirements are airborne sound insulation, impact sound insulation, facade insulation and equipments. Each country has adopted its own parameters to evaluate the requirements, depending on local building traditions and techniques and the values can be different depending also on the function of the building (residential dwellings, commercial buildings, offices, hotels, hospitals, educational spaces, entertainment, …).
The dynamic stiffness id the parameter that gives information about the elastic characteristics of a material in dynamic conditions. It is measured according to the standard EN 29052-1 through the determiantion of the resonance frequency of a mass-spring system, in wich the “spring” is the material under test. The value of the dynamic stiffness depends on the load applied to the material (the mass per m²), for this reason the standard prescribes a reference load of 200 kg/m². The dynamic stiffness gives a value to the capability of the different materials in attenuationg the vibrations. the lower is the value, lower is the frequency that can be insulated and the better is the global acoustic insulation.
How can be defined the thickness for a product for impact sound insulation applied under a screed in the floating floor technology?
The thickness of a product for impact noise insulation under a floating screed is not a simple dimensional evaluation of the mat or panel “”as is””, but it requires the use of a more complex procedure. A mat for impact noise insulation under load (a sand and cement screed 5 cm thick can have a weight of 90-100 kg/m²) has a thickness wich depends on the applied load itself. The standard EN 12431 provides a method to assess the thickness under load for such products and simulates the long time behaviour through the application of a very high load in a limited time.
The values resulting from this methodology are:
dL = thickness of the mat, measured at the load of 250 Pa for 120 seconds;
dF = thickness of the mat, measured at the load of 2000 Pa for 120 seconds;
dB = thickness of the mat, measured at the load of 2000 Pa, after an additional load of 48000 Pa for 120 s.
The comprimibilty is calculated from the difference between the dB and dF values.
The major problems regarding vibration in buildings refer to the disturbance from service equipments (generators, HVACs, …) or disturbance from the proximity of transport infrastructures (railways, metros, roads, …).
In the case of machinery, the vibration is cause by the rotation and movement of mechanical components that generat forces, due to the intrinsic unbalancing, that can be transmitted to the machine first, and then to the connected structures.
In the case of the transport infrastructures, the vibration are generated by the passage of the vehicle itself. In particular the contact between the wheel and rail (or tyre and road) is the cause of the generation and propagation of forces and vibration in the surrounding environment.
Can the installation of electric and idraulic equipment have an influence on the acoustic insulation?
I'm designing the acoustic insulation of a separation floor between two dwellings, which product should I choose?
I'm renovating an apartment and the owner does not want to demolish the existing screeds. Is there a solution?
Can the impact noise be reduced on the floor above, just by using an additional ceiling in the disturbed room?
To reduce effectively the impact noise it is very important to improve the floors from top, with a floating floor, because the noise and vibration energy can be blocked directly at the source. An additional ceiling gives a great improvement in the ariborne sound insulation of the floor, increasing the apparent transmission loss, but there is less influence on the impact noise attenuation (approximately 5 dB of improvement in the impact sound reduction). The use of an additional hanged ceiling and a floating floor together gives very high values of insulation, for both impact and airborne sound insulation. An inclusive solution is based on the simultaneous insulation of the floor, walls and ceiling and this gives a remarkable sound insulation by realizing a “box in a box”, in which all the insulation elements are installed according to the correct instructions and methods (wall claddings separated from the base wall, ceiling installed with damped hangers, …).
I want to increase the sound insulation of an existing wall, but I don't want to lose much space. Is there a solution?
What's the best method to soundproof an existing wall, a cladding with metal structure or in adherence?
I have to install a new press in the production. Is it possible to insulate the surroundings from vibration?
Safety flooring mats are chosen primarily for their HIC value: the playground equipments have different geometry and height, for this reason the choice of the most suitable safety mat allows to fit each equipment, avoiding and limiting eventual damage from falls. The thicker the tile, the safer is the application (higher critical fall height). The safety flooring mats are produced in different colours (red, green grey) and dimensions and a lot of accessories can be chosen, to make the installation nicer and safer.
Sound insulation in buildings is a very important requirement, to obtain the fitness for use for a dwelling. Differently from the thermal insulation, acoustic insulation does not provide saving in the mantainance costs of a building, but increases quality of life and work and the privacy inside buildings, reducing the fights between neighbours. A good acoustic insulation allows to use domestic rooms with a different purpose than the primary design (for example a living room with a Home Cinema, or a cellar used as music studio).
Installation & support.
A floating screed has to be completely separated from the walls and side structures, to work properly. For this reason, at the edges of the room the special perimetral bands Isolgomma Profyle are installed and the mat is laid on the whole floor. The mats should be installed without overlappings (to avoid thickness variations in the screed), positioning the mats adjacently without leaving any gaps and sealing the junctions with the built-in adhesive overlapping band. As alternative to the application of the perimetral bands, the mat can be folded vertically, to match the design height of the final floor. The screed can be a traditional sand and cement, or either a self-levelling screed (for example anhydrate), with a density of approximately 2000 kg/m³. The perimetral band should be left uncut until the final application of the ceramic tiles or parquet, and the exceeding parts should be cut only before the application of the skirting, carefully avoiding to connect it rigidly to the floor: the application of a siliconic sealant in the gap between skirting and floor is suggested.
How should the products for coverings (laminated with gypsumboard) be installed on an existing partition?
Who should I contact in case of any questions on technical or practical aspects regarding products or application?
Isolgomma is respresented locally by a net of distributors, that give an everyday support regarding technical and commercial requests. You can find our local distributor on the website at this link. For areas not covered by our network, contact Isolgomma directly at email@example.com