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Acoustics - laboratory measurement of sound insulation of building elements - Part 4

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Acoustics - laboratory measurement of sound insulation of building elements - Part 4

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... (1.2) is provided in the next chapter. Alternatively, sound intensity based method (ISO 15186 [16]) is also used for the SRI measurement which will be discussed later. For field conditions, ISO 16283-1 [17] method is used to measure the sound insulation. ...
... The transmitted sound power can either be calculated by an intensity approach [16] or indirectly by SPL measurements in receiving room as per ISO 3741. Using ISO 3741, the transmitted sound power level can be measured in one-third octave bands as, = 2 ( ) + 10 log ( 0 ) + 4.34 + 10 log (1 + 8 ) + 1 ( ) + 2 ( ) − 6 (6.9) ...
... 16 shows the reciprocity plots for the new test. It shows the reciprocity between the FRF's is far better (compared toFigure 3.14) which means correct data has been used. ...
Thesis
The thesis concerns with the development of novel measurement methods for characterisation and diagnosis of airborne sound transmission through building partitions. Using standard tests, the airborne sound insulation of partitions can be measured as the Sound Reduction Index ‘SRI’. While the SRI provides the frequency dependence of sound insulation (or transmission), the local/spatial sound transmission through various paths in the partition is not known. If the contributions of different paths in the partition can be measured then any weak paths of sound insulation can be diagnosed. This would be especially useful in the case of multi-layered partitions where the sound insulation depends on the sound transmission through point connections/ribs/studs/frame, etc. present in the structure. While different theoretical models are in place to predict the sound insulation in presence of such elements, the experimental diagnosis of their sound transfer contributions remains fairly unexplored. Similar diagnosis problems are encountered by automotive industry while dealing with structure borne sources in the vehicle. In practice, Transfer Path Analysis (TPA) methods are extensively used in such cases for diagnosing the contributions of different structure borne sources at vehicle interiors. Application of such TPA methods for diagnosing airborne sound transmission is challenging on various counts. Firstly, the airborne source applies a continuous excitation on the receiver as opposed to structure borne sources which are typically discrete. Secondly, for our study, the path contributions are desired which is difficult than measuring source characterisations. To address these issues, a novel TPA application Inverse-Airborne Source Contribution Analysis (I-ASCA) is devised which employs a patch based discretisation of the source receiver interface for the diagnosis of airborne sound transmission through partitions. Using such discretisation, the airborne excitation on the partition can be inversely characterised by blocked forces and the source contributions can be measured. Additionally, a new methodology Inverse Path Contribution Analysis (I-PCA) is outlined which allows for measurement of path contributions. These methodologies applied to the case of single and double layer partitions excited by airborne source and the accuracy of the methods was found to be within 2-3 dB of the measured response in general up to a maximum of 1 kHz under the tested grid size. The accuracy of the method is thus strictly linked to the discretisation size. A sampling criterion of 𝜆𝑏/2 was found to be sufficient which is less demanding than sampling criterion utilised by finite element methods. The methods can be applied to >1 kHz range if the discretisation can be made finer. To improve the practical application of the methods, the Direct-Airborne Source Contribution Analysis (D-ASCA) is presented which allows for direct characterisation of the airborne excitation using contact pressures. The method is much faster than I-ASCA in providing source contributions however path contributions cannot be measured using this method and the accuracy of the method is also found to be within 2-3 dB. D-ASCA application has been presented for the case of commercial single and double casement windows. Using careful assumptions, it is possible to estimate the path contributions of the glazing and frame in the windows from the source contributions. The diagnosis allows comparing the path contributions in frequency regions up to 1 kHz and the weak path is identified. This shows the potential of the method in identifying the weak elements of sound insulation which can be used as a complement to the SRI data and can provide cues for improving the sound insulation of the partition. Lastly, an in-situ measurement method for airborne sound insulation measurement is presented which can be applied when a pressure doubling occurs at the surface. A novel approach has been presented to assess whether pressure doubling occurs on the surface and calculating the blocked pressures. This allows one to measure SRI in-situ using diagnostic measurements without the need of a separate standard test for measuring SRI. This showcases the versatility of the approaches in that the frequency dependence (SRI) and spatial dependence (path contributions) of sound insulation/transmission can be measured within a single approach.
... Each hammer is cylindrical with a radius of 30 ± 0.2 mm and has an impacting surface that is spherical with a radius of 500 ± 100 mm. The time between succussive impacts is 100 ± 20 ms, for an effective impact frequency of 10 Hz [4]. ...
... An alternative impact source used outside North America is the ISO rubber ball, a hollow ball 180 mm in diameter with a thickness of 30 mm, a mass of 2.5 ± 0.1 kg and a coefficient of restitution of 0.8 ± 0.1, dropped from a height of 1 meter [4]. This impact source is particularly appropriate for acoustic measurements of lightweight floors due to its resemblance to human excitation in the low frequencies [10]. ...
Conference Paper
Full-text available
Impact testing has been in use since 1927 for acoustic testing of floor ceiling assemblies. The process used in the United States is defined in the ASTM E1007 standard. This testing method produces an Impact Sound Rating (ISR) which is a measure of the impact sound isolation between an upper and lower room and is used in industry for assessment and comparison of constructions. A standard tapping machine is used to generate an input force. The intent is to deliver a consistent input across all floors; however, the actual input force is dependent on the impedance of the impact device and floor. A soft floor may have a significantly different force than a hard floor. This variance is not accounted for when computing the ISR, resulting in less meaningful test results. This paper investigates an alternative method of impact force generation though the creation of a machine purpose built to measure the input force on any type of floor ceiling assembly. Measurement of the input force would allow for FRF calculations which may be a more informative method of sound isolation evaluation.
... The window outlets were small compared to the common wall area and the source room is not reverberant, making the sound transmission loss formula adopted in the standard BS EN ISO 10,140 [22] not useful. The classical room acoustics equation should be adopted instead, and the level of the transmitted power SWL t and the average sound level in the receiver room SPL rec are related to the room constant of the receiver room R rec as SWL t ¼ SPL rec À 10log 10 4 ...
... The TL EN1793 for all the five opened casement windows tested are all about 2 dBA. However, many of the one-third octave band TLs so calculated using the traditional ISO standard formula [22] are negative (not shown here), showing that the above proposed approach is valid and should be used. ...
Article
A parametric study on the traffic noise transmission loss across plenum windows was carried out experimentally in this investigation in an attempt to establish a simple empirical model for predicting this transmission loss. A total of fourteen full scale plenum windows were included in this study. The results of a site mockup measurement were used for model validation. The present model was developed based on the existing plenum chamber theory in which the sound fields inside the plenum window cavities were assumed to make up of a diffracted wave and a reverberant field. Results suggest that both the diffracted and reverberant field inside the plenum window cavities are weaker than those assumed in existing plenum chamber theory. It is found that a model, which assumes frequency-independent diffraction directivity and percentage reverberant field attenuation, gives the best prediction of traffic noise transmission loss. This prediction model is also able to predict site test results with good accuracy.
... Accordingly, models that can be employed at a design stage to predict the sound transmission of multi-leaf walls have to be validated on a case-by-case basis. Such models should also be able to predict the Sound Reduction Index at one-third-octave bands with sufficient accuracy in comparison with experimental data complying ISO10140 (23). Consequently, this work validates a Finite Element (FE) model to predict the acoustic insulation of double-leaf walls with slotted steel studs. ...
... Once the acoustic pressure domain is solved using FEA then the Sound Reduction Index (R) can be evaluated using Eq. (2), where L1 and L2 are the equivalent sound pressure levels, A2 is the equivalent absorption area, and S is the area of the dividing partition (23). The sound pressure level can be computed using Eq. ...
Conference Paper
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Acoustic bridging through structural links is known to reduce the Sound Transmission Loss (STL) of gypsum plasterboard partition walls with steel studs. As multifamily housing become more popular, stud manufacturers are increasingly interested in improving the acoustic characteristics of steel studs to improve the sound insulation. This work is an initial attempt to understand the influence of slotted stud configurations on the sound transmission loss (STL) of partition walls. A case of partition wall commonly known as the double-leaf wall incorporating various slotted stud designs are analysed numerically based on the ISO10140 guidelines. The numerical model used for the analysis is validated using experimental test at one-third-octave bands for a frequency range of 100 to 3150 Hz. The slot configurations are designed keeping the slot to non-slot area constant to identify the effect of slot location on the acoustic behaviour. The results of this study provide a better understanding of the acoustic performance of double-leaf walls that use slotted stud sections. It is considered that this can help in developing acoustically efficient stud based partition walls to reduce acoustic bridging.
... where V is the volume of the receiving room (m 3 ) and T is the reverberation time in the receiving room (sec). Background noise correction was also applied to the L 2 measurements [28]. The lower room was chosen as the source room, because of its larger volume [26], and space averaging was applied to L 1 , L 2 (equation (1)) and T (equation (2) ...
... ). For sound pressure level measurements, four loudspeaker positions were used (number determined following ISO 10140-5 [26]), together with five microphone positions (as recommended in ISO 10140-4 [28]). For reverberation time measurements, two source positions and three microphone positions were used, following the engineering accuracy method of ISO 3382-2 [29]. ...
... Theoretically, the Sound Reduction Index (SRI), as the basic measure of the sound insulation capability of a window, characterizes the proportion of incident sound energy that cannot transmit through its surface. To measure the SRI, ISO 10140 standards [12] specify the necessary requirements and practical guidelines for conducting the laboratory experiments. A schematic diagram of the test-rig is shown in Fig. 1, where the test specimen is mounted on a separation wall between a source and a receiving room. ...
... ISO 10140 suggests the use of a reverberant room to excite the test structure, so that the incident sound energy is uniformly distributed over the surface of the specimen [12]. This also enables the incident power to be characterized by averaging the sound intensity inside the source room. ...
... It implies 'intervening conditions' have inter-relationships with all the other themes in other categories. Similar to previous studies [26][27][28], the themes under 'intervening conditions' were found to be closely and reciprocally linked to the themes under the other categories. It was also found that attitudinal factors and noise sensitivity have close relationships with the themes under the other categories such as annoyance and coping, confirming the previous findings from environmental noise [18][19][20][21]. ...
... Two laboratory experiments were conducted to examine annoyance and physiological responses to floor impact noise [25]. Both experiments introduced two different floor impact noises induced by a standard heavyweight impact source (i.e., an impact ball [26]) and real impact sources such as human footsteps. The participants (N=21) in the first experiment rated annoyance to 8-second noise stimuli and their physiological responses were measured when 23-second noise stimuli were presented. ...
... The active test is the operational phase where the source excites the system and operational responses are measured. In iTPA, the blocked forces are then found as per equation (1). In equation (1), A is the accelerance matrix formed from FRF measurements, and a' is the operational acceleration vector; capital letters denote a matrix and lower case letters a vector. ...
... In iTPA, the blocked forces are then found as per equation (1). In equation (1), A is the accelerance matrix formed from FRF measurements, and a' is the operational acceleration vector; capital letters denote a matrix and lower case letters a vector. In this way, the blocked forces can be mapped onto the receiver surface points with the help of the path FRF's to determine the path contributions as will be explained below. ...
Conference Paper
Full-text available
The sound insulation of a building element is usually rated by relevant parts of ISO 101401 to give a single number quantity Rw - the Sound Reduction Index (SRI). These standard tests however, do not provide any information on how the sound is transferred through such an element or the contribution of the transfer paths involved to the total sound observed at a receiver position. Similar problems are also encountered in the automotive industry while dealing with NVH issues and these are generally tackled by use of methods such as Transfer Path Analysis (TPA). Such TPA techniques provide diagnostic information about the sound transfer paths in the structure subjected to an applied excitation usually structure borne sound. This paper highlights and discusses the novel use of an in-situ TPA technique adapted to the problem of diagnosing sound insulation transfer paths in cavity constructions subjected to airborne excitation. The accuracy of this method is dependent on the spacing of measurement points with respect to incident wavelength. Results are presented for the sound transmission through a cavity-backed plate and point connected plate constructions.
... The same set of microphone measuring positions was used for each applied actuation pressure. Based on those sound pressure measurements, the TL was calculated using the standardized procedure [28]. In accordance with the standards [28,29] and in order to ensure that a diffuse sound field was established within the given room dimensions, the lower limit of the measuring range was set at 0.5 kHz. ...
... Based on those sound pressure measurements, the TL was calculated using the standardized procedure [28]. In accordance with the standards [28,29] and in order to ensure that a diffuse sound field was established within the given room dimensions, the lower limit of the measuring range was set at 0.5 kHz. According to standard [29], the upper limit of the measuring range is 3.15 kHz. ...
Article
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Compressible Constrained Layer Damping (CCLD) is a novel, semi-active, lightweight-compatible solution for vibration mitigation based on the well-known constrained layer damping principle. The sandwich-like CCLD setup consists of a base structure, a constraining plate, and a compressible open-cell foam core in between, enabling the adjustment of the structure's vibration behaviour by changing the core compression using different actuation pressures. The aim of the contribution is to show to what degree, and in which frequency range the acoustic behaviour can be tuned using CCLD. Therefore, the sound transmission loss (TL), as an important vibro-acoustic index, is determined in an acoustic window test stand at different actuation pressures covering a frequency range from 0.5 to 5 kHz. The different actuation pressures applied cause a variation of the core layer thickness (from 0.9 d0 to 0.3 d0), but the resulting changes of the stiffness and damping of the overall structure have no significant influence on the TL up to approximately 1 kHz for the analysed CCLD design. Between 1 kHz and 5 kHz, however, the TL can be influenced considerably well by the actuation pressure applied, due to a damping-dominated behaviour around the critical frequency.
... These quantities have since long been measured by standardized tests now. In case of airborne sound insulation of building partitions, these standard tests [1] provide a single number rating which is often not descriptive of the diagnostic properties of the sound transfer paths in the partition. This could be especially important in case of multilayered partitions with stiffening elements such as point connections, ribs, and/or with absorbing foam. ...
... In iTPA, the blocked forces are then found as per Eq. (1). ...
Conference Paper
The airborne sound insulation of a partition is measured by relevant parts of ISO 10140 to thereby give a single number quantity Rw-the Sound Reduction Index (SRI). These standard tests however, do not provide any information on how the sound is transferred through the partition or the contribution of the transfer paths involved to the total sound observed at a receiver position. In the automotive industry, wide use is made of methods such as Transfer Path Analysis (TPA) which provide diagnostic information about the sound transfer paths of structure-borne sound in a structure subjected to an applied excitation. This paper highlights and discusses an in-situ TPA technique based on blocked force approach, applied to the problem of diagnosing sound insulation paths in cavity backed partitions subjected to airborne excitation. Results are presented for the sound transmission through a cavity-backed plate for airborne excitation and a point connected dual leaf partition for structure borne and airborne excitation. Flanking has to be minimal for validating the methodology in the case of airborne excitation. The path contributions measured in presence of other flanking paths are still valid and show if the partition under consideration is a dominant path for sound transfer with respect to the flanking paths. For structure borne excitation, an interesting application of the method is source localization.
... Vibrations velocity levels were measured according to EN 10848 [2], and sound pressure levels were measured according EN 140-4 [3] with the dodecahedron source, and according to EN 140-7 [3] with the tapping machine. Reverberation times were measured according to EN 3382-2 [4]. ...
... Vibrations velocity levels were measured according to EN 10848 [2], and sound pressure levels were measured according EN 140-4 [3] with the dodecahedron source, and according to EN 140-7 [3] with the tapping machine. Reverberation times were measured according to EN 3382-2 [4]. ...
... Standard test procedures [1] have been developed over the years for rating the performance of building elements with respect to airborne sound insulation, absorption, etc. These ratings are quantified by a single number or in third octave bands and, although convenient for comparing the performance of building elements, provide little, if any, information on how the sound transfer takes place and the contribution of various paths to the total sound transfer. ...
Conference Paper
Full-text available
Transfer Path Analysis methods are one of the most widely used techniques for diagnostic testing of structural and airborne sound transmission. Although widely used in the automotive sector, these methods however have not been adopted in the Building Acoustics domain and the paper intends to explore their usability in this context. Commonly used Inverse techniques such as Panel Contribution Analysis methods require extensive measurements usually involving reciprocal transfer functions and could be time consuming when the radiating structures/panels can be complex and large in size such as building elements. The presented work deals with defining an alternative method for predicting the receiving side pressure by using frequency response functions of the path and receivers and operational measurements. This removes the need for volume velocity sources and reciprocal measurement of frequency response functions. The accuracy of this method is dependent on the spacing of measurement points with respect to incident wavelength. Results are presented for the sound transmission through a cavity-backed plate.
... O estudo do desempenho acústico dos sistemas de piso flutuante, utilizando os materiais resilientes desta pesquisa, foi realizado através de ensaios laboratoriais na câmara de ruído de impacto do LNEC, em Lisboa -Portugal, de acordo com a ISO 10140-3[4]. O ruído foi gerado na sala de emissão através de uma máquina de impacto padrão 3207 Bruel & Kjaer em bandas de frequência de um terço de oitava, enquanto três microfones foram utilizados para adquirir os dados, na sala receptora. ...
Conference Paper
Full-text available
The acoustic performance of floor systems is directly linked to the specific characteristics of each material, but the behavior of these materials can be changed along time with the common use of the building. Therefore, the reduction of the resilient layer thickness of the floating floors represents a loss in efficiency of the acoustic system, which can be caused either by compressions along the life cycle of the building or the compressive loads resulting from accidental loads. These conditions may indicate that a same product can sometimes present different performances due to the different compositions of floating floor systems. This paper presents a study based on five different underlayers of floating floors. The underlayers were polymeric fibrous materials with densities between 180 and 1000 kg/m² which was evaluated before and after compression 122 days.
... The effectiveness of the partition wall materials and constructions in preventing sound transmission is assessed through a measurement of transmission loss, R, and a calculation of the Weighted Sound Reduction Index, Rw. Standard measurements in laboratory conditions are made using ISO 140-4 [1], or recent update [2], and are rated using ISO 717-1:2013, [3]. Compliance with the IMO code of practice of the International Maritime Organisation is required, [4], which specifies a minimum value of Rw = 35, but significantly higher values may be required for specific applications. ...
Conference Paper
Full-text available
The leisure marine industry is joining the composite revolution, bringing the advantages of lightweight, high stiffness and strength materials to the design of cabins for cruise ships. The weight reduction has the potential to provide significant fuel savings, but the acoustic insulation properties of composite partitions are not ideal, and meeting industry requirements for the acoustic performance is not straightforward. This paper describes a numerical approach to the prediction of the transmission loss and Weighted Sound Reduction Index of a panel undergoing a test in a laboratory, and corresponding values that would be measured in a field test between cabins on-board a ship.
... In buildings, the airborne sound transfer from one room to other is insulated primarily by installing partitions between the two rooms. The acoustic performance of such partition structures is described by its sound insulation and is quantified by a single number rating [1] as the Sound Reduction Index (SRI) or Sound Transmission Class (STC). However little is known about the nature or performance of sound transfer paths in the partition that contribute to the total pressure in a receiving cavity. ...
Article
Airborne sound transmission through building elements or the sound insulation of the building element is usually rated by its Sound Reduction Index (SRI) or the Sound Transmission Class (STC). SRI/STC quantifies the overall sound transfer but gives no information about how the transfer takes place and what are the contributions of different sound transfer paths involved. Such problems are fairly common to the vehicle acoustics industry and are generally tackled by TPA techniques. The paper formulates an in-situ Airborne TPA technique to quantify the contributions of different sound transfer paths to the transmitted pressure. The airborne source is characterized by its blocked pressure and its direct measurement is discussed. Results are presented for dual leaf partitions excited by an airborne source. The method has shown to be significantly faster than the Blocked force based TPA method which relies on inverse measurement methods. The accuracy of the method is closely related to the wavelength of incident airborne waves.
... The laboratory measurements were performed in accordance with the ISO 10140 [12][13][14][15][16] and EN ISO 717 10,11 standards. The test specimen was constructed at the Faculty of Engineering in the University of Porto's acoustic chamber ( Figure 2). ...
Article
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Historic buildings that regularly characterize the centre of our cities present us the challenge of being updated without losing their uniqueness. Acousticians frequently find themselves at the centre of this challenge, facing traditional solutions that must fulfil contemporary acoustical requirements. In order to apply technical improvements to enhance the performance of traditional solutions, the first step is to understand how these solutions work and perform in real-life conditions. Traditional solutions were conveniently tested by site measurements for validation. Airborne sound insulation (DnT,w) and impact sound insulation () tests were performed on 13 similar wooden floors. The same wooden floor was constructed at the Faculty of Engineering in University of Porto’s acoustic chamber in order to study its acoustical behaviour without the influence of flanking transmissions. Wooden floor improvement solutions were tested through the addition of airborne and impact sound insulation favouring materials. Airborne sound insulation (Rw) and impact sound insulation (Lnw) tests were performed on six solutions for the improvement of the traditional wooden floors. Traditionally, in Portuguese historical buildings, the lack of knowledge of the traditional solutions’ technical characteristics is sometimes the reason for demolishing these solutions. Adapting traditional solutions to current standards of comfort can become arduous since the information on the performance of these solutions is unknown. The potential demonstrated by these enhanced traditional solutions predicted a shift in current paradigms and will allow acousticians to support the challenge of historic building retrofit.
... The sound insulation between rooms was measured using the actual noise (which is similar to a road traffic noise) according to ISO 16283-1. This is the preferred method when the aim of the measurement is to evaluate the performance of a whole wall including all flanking paths [47]. The measured airborne sound insulation is frequency-dependent and can be converted, according to ISO 717-1 [43] into a single number quantity: the apparent sound reduction Index (see Fig. 11). ...
Article
This paper presents the evaluation of acoustic comfort for a conference room located in a sample of newly built public buildings. The inside and outside ambient noise, interior sound insulation and the reverberation time are measured according to international standards. Regarding acoustic requirements for spaces intended for speech communication, the results obtained from measurements are compared to those given as guidelines and reference values, and which are recommended by some national and international standards. This comparison reveals the existence of a poor acoustical quality in the conference room, and which is caused by a relatively excessive level of the ambient noise, low insulation between the technical and conference rooms and high value of the reverberation time. This inconvenient situation is attributed to deficiencies in concept details at the early building stages, and which is principally related to the inappropriate consideration of the acoustical aspects that the building is expected to fulfill. Some recommendations are consequently given and discussed for remedying this situation and improving the acoustics of the building.
... During independent research, carried out by the University of Padova and University of Bologna in recent years, 27 CLT floors were evaluated in laboratory, with and without toppings, both for impact noise and airborne sound reduction according to the relevant standards [8,9,10,11,12]. Measurements results were selected in order to compare between them only building elements based on the same type of CLT structure and with floating floor systems previously analyzed in laboratory on a concrete slab for the evaluation of the improvement of impact sound insulation, ΔL. ...
Conference Paper
Full-text available
The estimation of impact sound insulation of horizontal partitions, evaluated from the performance of basic components using EN 12354-2 Standard, do not actually provides satisfactory results when applied to the floors realized with cross laminated timber (CLT) elements. Among the possible reasons of this limited correspondence between predicted and measured impact noise values, one of the most interesting is the difficult to correlate the reduction of the impact sound pressure level of the floor covering, measured in laboratory on a concrete slab, with the actual behavior on a bare CLT floor. In this paper the results of a laboratory evaluations independently managed by different researchers on similar CLT structures is reported. The purpose of this study is to identify an empirical spectrum of the normalized impact sound pressure level of a reference floor realized based on CLT technology, in order to provide an useful and simple tool for estimate the noise insulation performances for this type of building element.
... Δ (dB) value shows how much impact sound pressure level reduces by adding an upper layer to the bare base concrete floor (with respect to that of the bare base floor). To determine this improvement (Δ ), it is necessary to perform measurements in the laboratory according to the requirements of LST EN ISO 10140 series standards [6][7][8][9]. It is required to use a large-scale specimen with an area of ≥ 10 m 2 . ...
Article
Full-text available
It is very convenient to evaluate new floating floor constructions by using a small size specimen (< 1 m 2) in real building instead of testing the same construction in a laboratory on a big area (≥ 10 m 2) specimen (as it is required by the standard). No information has been found in scientific literature about any research in which such small specimens (for example, 0.5 m 2) were used. Therefore a question occurred whether such specimens could in fact be used in practice instead of big ones (≥ 10 m 2) and if so, under what conditions. In order to answer this question, the first step is to study the previous research. It provides the ∆ values of small size specimens and how they differ (are smaller) from those of big specimens. As a result of this, a new question has arisen whether the shape (the ratio of the sides of a rectangular specimen) of the specimen does have an influence on the results (∆) or whether only the size of the specimen (area) influences it. In this experiment, the specimen shape was changed from rectangular to square (though maintaining the same specimen's area of about 0.5 m 2). The results of the experiment showed that different shapes of a small specimen have negligible influence on ∆ value. Moreover, the experiment results, which provided some answers to previously mentioned questions, led us to offer evaluation methodology for determination and compensation of ∆ measurement methodology errors, which are hypothetically independent from physical parameters of floating floor construction components using small area (0.5 m 2) specimens. In order to be sure of the correctness of the presented methodology, a reinforcement of further investigation is required.
... The sound reduction indexes of those two walls were taken from laboratory certificates, following to (UNI EN ISO, 2010). ...
Conference Paper
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Until now, design of new high performance buildings has been focused on the energy performance but lacks to be addressed as a holistic problem taking into account all the aspects of a performance of a building. This work strives to study and optimize at once, the energy performance of a building and the sound insulation performance of its facades. In particular, energy and acoustic performances of different building facades, made of two different wall types, were compared taking in account the cost-optimized design of a building. The proposed methodology couples a cost-optimization of the building energy model made though TRNSYS ® and GenOpt, with an evaluation of the sound insulation indexes with Matlab ® , and it was applied to a French single-family case study. The results show that the cost optimal energy performance level of such case study is somewhere between 40 and 47 kWh/m².year, while the sound insulation efficiency of the façade can reach a wide range of values. However, the proposed methodology allowed to highlight several design solutions fulfilling the requirements in term of energy, cost and acoustics performances. .
... The study was conducted in 13 buildings and the floor solution was chosen by the same criteria: floors with the same type of solution. The site measurements procedure follows the EN ISO 16283 8,9 and EN ISO 717 10,11 standards. Tables 1 and 2 show the tested floors' different characteristics found in the buildings under this study. ...
... During independent research, carried out recently by the Universities of Padova and Bologna, 27 CLT floors were evaluated in the laboratory, with and without toppings, for impact noise and airborne sound reduction according to the relative standards. 8,9,10,11,12 Measurement results were selected to compare only building elements made with the same type of CLT structure and with floating floor systems previously analysed in the laboratory on a concrete slab to evaluate improved impact sound insulation (?L). ...
Conference Paper
Estimation of the impact sound insulation of horizontal partitions, evaluated from the performance of basic components according to EN 12354-2, does not provide satisfactory results when applied to floors made of Cross-Laminated Timber (CLT) elements. One of the most interesting reasons for this limited match between predicted and measuredimpact noise values is the difficulty of correlating the reduction of the impactsound pressure level of the floor covering, measured in a laboratory on a concrete slab, with the actual behavior on a bare CLT floor. Reported here are the results of laboratory evaluations, independently carried out by various researchers on similar CLT structures. The purpose of this study is to identify the empirical spectrum of the normalized impactsound pressure level of a reference floor made according to CLT technology, to provide a simple and useful tool for estimating the noise insulation performances of this type of building element.
... Al foams can be generally classified into open and closed-cell according to pore interconnectivity [58]. Closed-cell Al foams are usually favoured for their Sound Reduction Index (R) [59,60] rather than absorption due to their lightweight properties. ...
Chapter
Metallic foams are among the most promising class of materials due to their unique mechanical properties combining low mass with high stiffness, excellent energy absorption, and vibroacoustic damping. Consequently, noise control using methodically engineered metallic foams has received increased attention from both industrial and scientific community. Accordingly, this paper aims to present the mechanism of sound absorption along with the experimental and theoretical procedure that can be used to classify metallic foams. Additionally, the influence of design parameters on the resulting sound absorption coefficient of closed and open-cell metallic foams are explored. While Aluminium foams used to dominate the literature when it comes to acoustics, recent studies have reported Nickel-Inconel superalloy and Copper foams as having superior sound absorption coefficients.
... Methods of measurements of noise, vibrations and other acoustic parameters of environment, materials or constructions including evaluation processes are defined in relevant technical standards (e.g. [2][3][4]). The main parameter of the environment is the equivalent level of acoustic pressure, while the parameters of materials or constructions are represented mainly by acoustic absorption, impact sound insulation or airborne sound insulation. ...
Conference Paper
Ensuring of acoustic comfort belongs among the most important functions of building envelopes since too high level of noise may have negative effects on people living inside. Development of building elements with excellent acoustic properties is therefore one of objectives of current building industry. Methods of measurement, testing and evaluation of acoustic properties of building materials or construction are subjected to set of relevant standards. However, the standard procedures do not provide proper conditions for an effective research and development as they are time and cost ineffective. Utilization of modern techniques such as computational modelling of sound propagation and attenuation may represent the solution of this issue as it allows developing and testing the elements without being produced. At the same time, full- or semi-scale test constructions do not have to be built either within the development stage and they can be used effectively only for testing of final products in order to validate the results of computational modelling. Selection of proper mathematical and physical model is the crucial factor that ensures reliable data. The review of the available models is therefore presented in this paper, assessing each model briefly. Finally, the recommendation for selection of the model for description of sound propagation in porous materials is made.
... The highest difference observed was 0.39 dB at 500 Hz for TL as shown in Fig. 7a. This is well below the ISO10140 [48] defined measurement uncertainty as shown in Table 3. ...
... The formula proposed to validate the correlation between sound insulation of façade and exterior noise level is expressed by the Equation 1: (2) where D2m,nT is the standardized level difference defined in ISO 16283-3 (14); Ctr,50-3150 is the adaptation term as defined in ISO 717-1 (15); Lden, indoor is the indoor day -evening -night -weighted sound pressure level, with the appropriate weighting for the day, evening and night period, in the frequency range from 50 to 5000 Hz, as defined in the END for the Lden descriptor. ...
Conference Paper
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In recent years the acoustic qualification of buildings has gained more and more importance at international level. One of the central elements for determining the sound quality of houses is the insulation against external noise. In fact, many issues related to excessive noise in dwellings arise from their inclusion in noisy environments, or from their original surrounding environment, which has grown from silent to very noisy over the years. The main strategy to limit the noise inside the buildings is the façade insulation improvement. Regulatory requirements and classification schemes in Europe present a high degree of diversity. In particular, the approach to the façade insulation acoustic requirement adopted is very different in the various countries also because it is closely related to the outdoor environmental noise. The main issues related to the façade sound insulation are investigated with particular focus to the choice of the descriptors, the evaluation methods and their reproducibility. The latter aspect is the more difficult to evaluate.
... In buildings, the airborne sound transfer from one room to other is insulated primarily by installing partitions between the two rooms. The acoustic performance of such partition structures is described by its sound insulation and is quantified by a single number rating [1] as the Sound Reduction Index (SRI) or Sound Transmission Class (STC). However little is known about the nature or performance of sound transfer paths in the partition that contribute to the total pressure in a receiving cavity. ...
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The airborne sound transmission through a building element such as a partition/panel is governed by the sound insulation of the partition, or the resistance the partition provides to the incident sound. Typically the airborne sound insulation of the wall is rated by a single number quantity given as the Sound Reduction Index (SRI) or the Sound Transmission Class (STC). However these ratings do not provide any information on the sound transmission through different paths in the partition. Such information may be useful in diagnosing weak sound insulation paths, weight optimisation, etc. The Airborne TPA method based on blocked force formulation has proven to be an effective technique to diagnose the sound transfer through individual paths. The paths can then be rated according to their sound pressure contributions. The Airborne TPA method however , can be time consuming in case of limited number of sensors and/or large size of partitions. Hence there is a need to provide a faster measurement method which would provide the diagnostic information about the sound insulation paths. In this paper, a simplified Airborne TPA approach based on measurement of blocked pressures is presented. The blocked pressure theory for the airborne sound transfer through partitions is discussed at first. Validation and diagnostic results are then presented for sound transfer through point connected dual leaf partition using the new approach. The blocked pressure method is significantly faster and can be automated. The accuracy of the measurement is dependent on the wavelength of the incident wave.
... A noise measurement was performed based on measurement and analysis criteria, 31 which are widely used to measure the noise reduction performance of the bellows. The reverberation chamber method was used to calculate the sound absorption rate and transmission loss for a test membrane using the reverberation time. ...
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Chapter
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Chapter
This chapter explains the development of regulations as a part of a noise management concept. The legal dimensions on strengthening enforcement for noise control extended widely throughout Europe; for example, the first noise regulations were decreed in The Netherlands in 1979, in France in 1985, in Spain in 1993, and in Denmark in 1994. The major international bodies paying great attention to environmental noise as health and wellbeing issues are: The International Civil Aviation Organization, United Nations Economic Commission for Europe, Organisation for Economic Co‐operation and Development, and World Health Organization. The development of noise regulation is an important part of noise management and action planning to protect the health and well‐being of individuals and the community against environmental noises. Successful noise management relies on good training and sufficient knowledge for those who will be involved with the preparation of the action plans and implementation at different stages.
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The European directives on noise reduction associated with buildings, rail, road and aviation clearly depicts the need for high efficiency sound attenuating structures for targeted noise reduction. Accordingly, this paper presents key observations from Phase 1 of the UK Department of Transport (DfT) funded research to investigate the targeted creation of acoustic interference to develop high-efficiency noise reducing structures. Geometrical cavities inspired from existing theories around the Herschel-Quincke concept is experimentally investigated for the creation of frequency dependent acoustic interference. The interference cavity within a global structure was digitally conceived and prototyped using the Selective Laser Sintering (SLS) process in a Nylon 12 material. A modified impedance tube method was then used to measure the frequency dependent Sound Reduction Index (R) for a frequency range of 250 to 1600 Hz. The results showed that depending on the frequency of interest, acoustic interference can be recreated by controlling the cavity length. In addition peak R values of 72.47 dB was observed at 900 Hz confirming the potential of the technology for high efficiency noise reducing structures. The observations presented in this paper establishes a new viewpoint in the use of acoustic interference for targeted noise abatement.
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Noise control is an environmental problem of first magnitude nowadays. In this work, we present a new concept of acoustic screen designed to control the specific noise generated by transport infrastructures, based on new materials called sonic crystals. These materials are formed by arrangements of acoustic scatterers in air, and provide a new and different mechanism in the fight against noise from those of the classical screens. This mechanism is usually called multiple scattering and is due to their structuring in addition to their physical properties. Due to the separation between scatterers, these barriers are transparent to air and water allowing a reduction on their foundations. Tests carried out in a wind tunnel show a reduction of 42% in the overturning momentum compared to classical barriers. The acoustical performance of these barriers is shown in this work, explaining the new characteristics provided in the control of noise. Finally, an example of these barriers is presented and classified according to acoustic standardization tests. The acoustic barrier reported in this work provides a high technological solution in the field of noise control.
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Façade airborne sound insulation is crucial for protection of indoor environment from environmental noise. In Turkey, sound insulation in new buildings is bound by law, but 6 million pre-1980 dwellings with thin brick walls and single-glazed windows used in highly transparent façades should be retrofitted. In this study, sound reduction index of masonry and cavity exterior walls which consist of brick, mortar, gypsum board and mineral wool and of common window types is measured in sound insulation test rooms. The study compares and evaluates the effects of plaster, brick thickness, cavity depth, mineral wool thickness and mineral wool placement on sound reduction index values, using traditional materials and building techniques. Traditional brick wall façades and possible retrofitting of these façades are evaluated for sound insulation of bedrooms and living rooms in different noise zones, 55, 60, 65, 70 and 75 dBA, with various transparency ratios, 0%, 30%, 40%, 50% and 70%. The analysis shows that window types and single-layer walls are the deterministic factors in evaluating sound insulation in retrofitting projects and that it is not possible to provide proper aural comfort in high noise zones.
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The present study describes the acoustical characteristics of the new noise barriers which can control not only noise but also wind pressure by allowing air flow through barriers. In order to investigate the sound reduction index of the air transparent noise barrier, 17 models in total were examined with various size of openings and the volume of the resonators. As a result, it was found that the sound reduction index varies with the volume of the resonator and the area of the openings. Also, it was revealed that double layer of units has more sound reduction index than the single layer of unit at the frequency band from 400 Hz to 1250 Hz. This denoted that physical features of openings and resonators affect the sound reduction index of the air transparent noise barrier.
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To design a sound-absorbing panel, it is important to identify factors that affect the maximum sound absorption of low, middle and high frequency sounds. Perforation effect is very important for the noise-reducing and noiseabsorbing panels. Perforations are often used for sound reduction. Experimental data shows that the perforation is very effective to absorb low-frequency noise. In the presented study, influence of perforation coefficient of noise reduction was analyzed with theoretical and experimental methods. The experiments were conducted in noise reduction chamber using an perforated construction with glass wool filler. Sound reductions index of 15 dB indicates good acoustic properties of the panel.
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France like some European countries takes into account intrinsic acoustic performance of floor coverings to reach building regulation requirements in terms of impact noise level. In this context PVC floor covering market developed in France yielding to the performance certification of these products under the label UPECA+ about ten years ago. The concerned industrials gathered within the SFEC (Syndicat Français des Enducteurs Calandreurs) anxious to answer market questionings about the time durability of their performances launched a wide study on the subject in collaboration with the CSTB and the support of the DGUHC (housing ministry). Six products have been followed during five years both in laboratory (natural aging without particular promptings) and in-situ (two lived-in housings). Intermediate observations of in-situ measurements campaigns led us to complete these investigations by a study on temperature base floor impact on acoustic performances. The main results are the time stability of acoustic performances of certified products as well as their strong dependency on surface base floor temperature.
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