Sound Insulation In Buildings Research Articles

Environmentally-Friendly Recycled Leather‑Reinforced Composite: Thermal and Acoustic Properties

Increase in energy consumption and environmental pollution are some of the main problems of today. One of the ways to overcome these problems is to increase the use of recycled materials. Heat and sound insulation in buildings can play an important role in saving energy and reducing environmental pollution with composite materials made from recycled leather. This study investigates the possibility of reusing leather scraps. Composite material was produced by cutting leather waste for thermal and sound insulation of buildings into small pieces and pressing them in a mechanical mold using polyvinyl acetate binder. The effect of the thickness of the developed new leather-added composite materials on their thermal and acoustic insulation properties was examined. When the thermal and acoustic properties of the composites were evaluated, it was determined that the PVA/skin thicknesses forming the mixture varied depending on the mean temperature and frequency (Hz). As a result of the measurements, it was seen that the sound at the 3000 Hz frequency, to which the human ear is most sensitive, was absorbed by 61%.

Calculating Flanking Transmission for Improved Airborne Sound Insulation in Buildings

The complexities of airborne noise insulation in tropical buildings provide challenges for predicting the value of airborne noise in buildings. The analysis employs standardized metrics, the Weighted Sound Reduction Index (DnT,w), to evaluate the impact of wall, floor, and ceiling combinations on acoustic performance. Notably, the study addresses the persistent challenge of flanking transmission, contributing to disparities between predicted and measured values. This study focuses on common construction materials in Indonesia. The outcomes reveal that lightweight construction materials, such as lightweight brick walls, consistently exhibit superior sound reduction, emphasizing their potential benefits in tropical regions. Additionally, the choice of ceiling materials, particularly gypsum board over wooden ceilings, significantly influences acoustic outcomes

Fabrication of composite aerogels from waste tires and fly ash for thermal and acoustic insulation applications

Recently, extensive research has been conducted on composite aerogel materials fabricated using industrial waste sources. These aerogels can not only help solve the most challenging environmental issues brought on by waste streams, but are also materials with excellent properties for thermal and acoustic insulation applications. This study, therefore, focuses on synthesizing composite aerogel using waste tire rubber powder and fly ash attained from power plants in a simple and environmentally friendly manner. The results show that the composite aerogel has a very low density (0.055- 0.079 g/cm3), a porosity of up to 96.57%, low thermal conductivity (0.022-0.039 W/m.K), an adequate noise reduction number (NRC) (0.41 at 250-4000 Hz) and high compressive Young’s modulus (120.5 kPa). These properties show the high potential of the material for thermal and sound insulation of buildings. Especially in the context of utilizing a reasonably priced source of waste material.

The strong influence of small construction errors on sound insulation of buildings with heavyweight concrete structure: A Portuguese case study

In order to attain an expected sound insulation in buildings, it is necessary to employ appropriated constructive solutions, but it is also fundamental to guarantee compatibility with other involved design professional fields, proper detailing of solutions and correct on site mounting. A solution with a predicted high acoustic performance may result in failure if there is no proper interconnection between other design professional areas or if execution mistakes occur, even if of very small dimension. The main objective of this technical paper is to analyse the influence of defects that typically occur in buildings, located in Portugal, resulting in very poor airborne or impact sound insulation performance. The chosen situations refer to buildings with heavyweight concrete structure, where small construction defects occurred and/or wrong decisions were taken, ending up with a large reduction on the final acoustic performance. Some of these errors, given their small size or because they occurred in hidden zones, easily passed unnoticed, on site. The defects here addressed in what refers to airborne sound insulation are related with execution of double masonry hollow brick walls, sound bridges in acoustic suspended ceilings, passage of ventilation or sewage pipes, inappropriate installation of acoustic doors, shutter boxes or windows. As for impact sound insulation, the presence of rigid connections is the main focus of the characterisation here performed.

Single-number values versus subjective judgment of airborne sound insulation in dwellings

There is a long history of adapting airborne sound insulation in buildings to the actual needs. A first pan-European work was published with COST Action TU0901: Integrating and Harmonizing Sound Insulation Aspects in Sustainable Urban Housing Constructions in which the differences between the sound insulation measure and the standard sound level difference were documented. Furthermore, ISO 16283-1: Field measurement of sound insulation in buildings and of building elements—Part 1: Airborne sound insulation states: Compared to DnT, R’ has a weaker connection to the subjective impression of airborne sound insulation. To investigate this relationship a simplified listening test and a computer-simulated variation studies of a synthesized airborne sound insulation were carried out. A test sound was generated from a speech, a music, and a noise signal, each of which was filtered by six frequency responses of solid structures. In a paired comparison task, 16 participants judged the loudness of the resulting 18 sounds. The results of the listening test show that perceived loudness is significantly correlated to the single number quantity DnT,w but less to the single number quantity R’w. This finding was confirmed across all signal types. Thus, the results confirm the statement in ISO 16283-1, that the single number quantity DnT,w has a stronger connection to the subjective impression of airborne sound insulation as the quantity R’w.

How the COVID-19 Pandemic Muted and Remixed the World's Acoustics for a While.

Purpose of ReviewThis review aims to analyze the effects of the pandemic on the world’s sound environment.Recent FindingsThe confinements associated with the pandemic led to a reduction in sound levels worldwide and a change in the perception of soundscapes in the absence of traffic noise and human-generated noise.SummaryIn response to the COVID-19 pandemic, many countries and regions around the world adopted a series of interventions in 2020 that have been referred to as “lockdown” or “confinement.” These sets of restrictions had a clear and obvious consequence derived from the absence of people in the streets and the reduction of daily activity and commuting, which caused an unprecedented silencing on a large scale. Along with the silence that ensued, the pandemic and the confinements affected acoustics and our relationship with sounds on different scales. In the cities, this phenomenon had a strong reduction in acoustic intensity due to the absence of vehicles on the streets. Perhaps this was more perceptible in our neighborhoods, with notable changes in their soundscapes, first due to the absence of people in the streets and later due to more outdoor activity derived from the fear of the spread of the virus in indoor spaces. The longer periods of time spent in our homes during the lockdowns also highlighted the importance of sound insulation in buildings and the acoustic conditioning of our schools or homes.

Research of sound insulation frequency response for a multilayer inhomogeneous wall structures

The object of research is the amplitude-frequency characteristic of sound insulation of multi-layer heterogeneous structures. One of the most problematic places is the calculation methodology, due to the existence of standards such as ISO, DBN, which have some differences between them, and software, the calculation methodology of which is not fully known, due to the copyright of the latter. Using the modeling method in the INSUL software complex, the amplitude-frequency characteristics of the sound insulation of the partition walls between the halls were obtained. On-site measurements were carried out on a real object identical to the simulated fence constructions presented by the MULTIPLEX cinema in the DAFI shopping center in Dnipro (Ukraine). The calculation methodology of the INSUL software is completely unknown. According to information from open sources, it can be concluded that linear modeling of the amplitude-frequency characteristic is used. The measurements were carried out according to DBN B.1.1-31:2013. Data obtained theoretically, during modeling, and experimentally are compared with each other. The expediency of taking into account the results obtained with the help of the INSUL software when writing a new methodology for the state standard or for improving the latter is considered. Comparing real and simulated amplitude-frequency characteristics, it is possible to conclude that the INSUL software complex is not accurate at high frequencies. This phenomenon may be related to the inherent resonances of the existing partition, or to the quality of the installation, which can be equated to a setup error, due to the lack of possibility of influencing the quality of the construction process of the measurement object. A possible error occurs when the soundproof partition is violently connected to the existing structures of the building, or due to the presence of resonating technical elements in the cinema hall (air ducts, metal structures of the stage and seats, etc.). This error is not influential due to the not significantly small wavelength in the frequency of 3000–8000 Hz. Therefore, as a conclusion, the INSUL software can be used in the development of the methodology of state standards for sound insulation in buildings.

System of national standards for measuring and evaluating sound insulation

The features of international standards being introduced in the Russian Federation in the field of measurement and rating of sound insulation are considered. It has been noted that over the past eight years, on the basis of international standards, a system of fundamental national standards of Russia has been created to measure and evaluate sound insulation in buildings and elements of buildings and structures. The system includes five standards that establish technical methods for laboratory measurements of airborne and impact sound insulation, a standard that establishes approximate methods for field measurements of airborne and impact sound insulation, two standards for a single-number assessment of airborne and impact sound insulation, a standard that sets the rules for determining and application of the uncertainties of sound insulation measurement. In 2018, 2019, on the basis of international standards, drafts of two national standards were prepared on the methods of field measurements of sound insulation of building facades and their elements and sound insulation of airborne sound between two rooms in a building.

Interactive real-time auralization of airborne sound insulation in buildings

Sound insulation auralization can be used as valuable tool to study the perceptual aspects of sound transmission in built environments for assessment of noise effects on people. It may help to further develop guidelines for building constructions. One advanced goal of real-time sound insulation auralization is to appropriately reproduce the condition of noise effects on the human perception and cognitive performance in dynamic and interactive situations. These effects depend on the kind of noise signal (i.e. speech, music, traffic noise, etc.) and on the context. This paper introduces a sound insulation auralization model. The sound insulation filters are constructed for virtual buildings with respect to complex sound propagation effects for indoor and outdoor sound sources. The approach considers the source room sound field with direct and diffuse components along with source directivity and position. The transfer functions are subdivided into patches from the source room to the receiver room, which also covers composite building elements, thus providing more detail to the actual building situations. Furthermore, the receiving room acoustics includes the reverberation of the room based on its mean free path, absorption and binaural transfer functions between its radiating walls elements and the listener. This more exact approach of sound insulation model agrees reasonably well with the ISO standard (i.e. diffuse field theory) under standard settings. It is also shown that the sound field significantly influences the transmitted energies via building elements depending on the directivity and position of the source. The proposed method is validated as a general scheme and includes more details for real-time auralization in specific situations especially in the cases where the simplified diffuse sound field approach fails. It is capable to be used in interactive Virtual Reality (VR) systems, which opens new opportunities for psychoacoustics research in noise effects on human.

Method of Calculation Multilayers Construction

Most shopping and entertainment buildings (shopping malls, concert halls, exhibition centers) are hangar type buildings. In malls there is a widespread placement of water parks, go-karts, cinemas etc. For example, the Ocean Plaza shopping mall, Dream Town and more in Kyiv. Music in concert halls, sound design of exhibition centers, restaurants, shops, the noise of water systems in water parks, the sound of movie in movie theaters - this is the noise that spreads to the surrounding buildings. Shopping centers are located in close proximity to residential buildings, leading to the need to provide sound and sound insulation of buildings around. The way to solve specific technological problems depends on the type of noise, the functional purpose of the buildings and the operational requirements. In apartment buildings, partitions and load-bearing walls are just a barrier to the propagation of sound waves. However, to be completely independent of noise and not to disturb neighbors, the problem can be solved very easily - it is necessary to carry out sound insulation. Modern methods of calculating the sound insulation of multilayer non-uniform structures widely used in modern construction are considered. Calculations of similar designs were carried out, modern software and domestic construction norms were used. After analysis, we found the shortcomings of both, and developed their own methodology for calculating such structures, based on theoretical methods of domestic State Building Standards, New Zealand software INSUL, and practical results of calculations of such structures. Conducted a comparative analysis of these techniques. Current methods of calculating sound insulation are very similar and have minor differences. The general method of calculation is outlined. In addition, one of the calculation options may be INSUL Software. Its convenience is that it has a large base of materials and structures, often used on real objects. Another advantage is the friendly interface of the program. However, the downside is the price of the software and the lack of a trial version. The problem of sound insulation of roofs is solved by the addition of sheets GKL, but, unfortunately, the installation of fire systems, lighting systems, smoke ducts violates the integrity of the floor, which leads to deterioration of noise protection. Currently, there are no regulations in the country to calculate the sound insulation of multilayered structures, such as our flexible roof. Compared to INSUL software and methodology developed. The latter needs improvements and fixes.

CRITICAL REVIEW OF METHODS FOR EVALUATING ACOUSTIC CHARACTERISTICS OR PREMISES

Introduction: The development of effective structural materials with improved acoustic characteristics is relevant for the modern construction industry. Considering the variety of international building standards for acoustic insulation and soundproofing of buildings, it is essential to systematize the modern methods of studying these characteristics. The purpose of the study was a comprehensive review of methods for determining acoustic characteristics in construction, as well as an analysis of literature and international standards to improve the health and comfort of the urban population.Main part:Due to the variety and complication of the study of the acoustic characteristics of buildings, premises and individual walling, the article provides an analysis of methods for evaluating these characteristics. The limitations on the size of rooms and sound frequencies for measuring reverberation time have been identified. The process of improving the method of measuring acoustic impedance in Kundt’s tube is shown. The methodology for determining the numerical parameters of sound insulation in buildings using the study of building envelopes taking into account the spectra of various noise sources located inside and outside the building is considered in detail. It was found that existing methods for measuring impact noise show poor reproducibility in the low frequency range. The analysis of the works proved that the sound reflection characteristics theoretically depend on the thickness and rigidity of the reflecting surface and its surface density.Conclusions: The scope of building materials with improved acoustic characteristics is quite extensive. Further research may be aimed at improving methods for studying the characteristics of sound absorption and sound reflection.Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.

Acoustic, Mechanical and Thermal Properties of Green Composites Reinforced with Natural Fibers Waste.

The use of acoustic panels is one of the most important methods for sound insulation in buildings. Moreover, it has become increasingly important to use green/natural origin materials in this area to reduce environmental impact. This study focuses on the investigation of acoustic, mechanical and thermal properties of natural fiber waste reinforced green epoxy composites. Three different types of fiber wastes were used, e.g., cotton, coconut and sugarcane with epoxy as the resin. Different fiber volume fractions, i.e., 10%, 15% and 20% for each fiber were used with a composite thickness of 3 mm. The sound absorption coefficient, impact strength, flexural strength, thermal conductivity, diffusivity, coefficient of thermal expansion and thermogravimetric properties of all samples were investigated. It has been found that by increasing the fiber content, the sound absorption coefficient also increases. The coconut fiber-based composites show a higher sound absorption coefficient than in the other fiber-reinforced composites. The impact and flexural strength of the cotton fiber-reinforced composite samples are higher than in other samples. The coefficient of thermal expansion of the cotton fiber-based composite is also higher than the other composites. Thermogravimetric analysis revealed that all the natural fiber-reinforced composites can sustain till 300 °C with a minor weight loss. The natural fiber-based composites can be used in building interiors, automotive body parts and household furniture. Such composite development is an ecofriendly approach to the acoustic world.

Laboratory and In-Situ Measurements for Thermal and Acoustic Performance of Straw Bales

This paper investigates the performance of timber-framed walls insulated with straw bales, and compares them with similar walls containing expanded polystyrene (EPS) instead of straw bales. First, thermal conductivity, initial water content, and density of the straw bales were experimentally measured in a laboratory set-up, and the dependence of the thermal conductivity of the dry material on temperature was described. Then, the two insulation solutions were compared by looking at their steady and periodic thermal transmittance, decrement factor, phase shift, internal areal heat capacity and surface mass. Finally, the acoustic performance of both wall typologies was analyzed by means of in situ measurements in two-story buildings built in Southern Italy. The weighted apparent sound reduction index for the partition wall between two houses and the weighted standardized level difference for the façades were assessed based on ISO Standard 16283. The results indicate that the dry straw bales have an average thermal conductivity of k = 0.0573 W/(m·K), and their density is around 80 kg/m3. In addition, straw bale walls have good steady thermal performance, but they still lack sufficient thermal inertia, as witnessed by the low phase shift and the high periodic thermal transmittance. Finally, according to the on-site measurements, the results underline that the acoustic performance of the straw bale walls is far better than the walls adopting traditional EPS insulation. Overall, the straw bales investigated are a promising natural and sustainable solution for thermal and sound insulation of buildings.

Improving building envelope performance with respect to thermal, sound insulation, and lighting: a case study

This study concerns an overall evaluation of building envelopes, for what concerns the energy, acoustic and lighting performances. It combines different topics of energy and indoor comfort, with the aim to improve the livability of an existing building (a social housing) by means of a comprehensive retrofit of their envelopes. The novel contribution of this study is to apply some methods for energy retrofit of a building envelope in such a way that objectives are achieved within the state-of-the-art combination simulation, optimization approaches, and equations describing the calculations of sound insulation in buildings. The results showed that properties of building envelope like the value of transmittance of the glass window and thermal properties of materials have an impact on indoor environmental quality and energy performance.

Advanced fabrication and multi-properties of rubber aerogels from car tire waste

For the first time, recycled car tire fibers (RCTF) shredded from car tire waste are developed successfully into a novel material, a rubber aerogel, using polyvinyl alcohol (PVA) and glutaraldehyde (GA) as crosslinkers through a cost-effective freeze-drying method. Its structure and main physical properties are investigated comprehensively for high-value applications, such as heat and sound insulation of buildings and oil spill spilling clean up. The rubber aerogel has ultra-low density (ρa = 0.035 – 0.145 g/cm3) and high porosity (Φavg = 84.31–96.20 %). With a simple but effective coating method with methoxytrimethylsilane (MTMS), both the interior and exterior of the whole rubber aerogel surface can be well coated, and the coated aerogel exhibits a super-hydrophobicity with a water contact angle of up to 134.4°. The rubber aerogel exhibits excellent heat insulation properties (Kavg = 0.035 – 0.047 W/m.K), very good thermal stability up to 500 °C, and significantly-enhanced rigidity up to a Young modulus of Eavg = 458.12 kPa, much larger than that of commercial Styrofoam. The rubber aerogel shows very good durability as it springs back to its original shape after compression tests. The rubber aerogel has a noise reduction coefficient (NRC) of 0.41 and performs approximately 10% better than commercial sound foam absorber at 2000–3000 Hz. The maximum oil absorbtion capacity of the rubber aerogel in this work is 19.3 g/g, very competitive to commercial sorbents. The fabrication method can also be scaled up for several other industrial applications, not limited to sound, heat and sorbent applications.

Balancing of constructional sound insulation according to DIN 4109:2016‐07 for residential buildings of lightweight concrete

AbstractMusic, talking, traffic noise: even supposedly slight noise nuisance can harm health in the long term. Permanent exposure to normal domestic noise, for example, can lead to a disruption of concentration – loud traffic noise can even lead to an increased risk of heart and circulation complaints. Constructional sound insulation is one of the most important protection aims in building. Improvement of the verification of sound insulation was the main aim of the revision of the DIN 4109:2016‐07 ”Sound insulation in buildings“. Particularly building with lightweight concrete offers several advantages in sound insulation, which have now also been covered in the standard.

Improvement of impact sound insulation: A constitutive model for floating floors

Floating floors have a high potential for reducing disturbance by impact noises in dwellings, since it greatly reduces the vibrations transmission through structures. The acoustical performance of a floating floor is quantified in terms of improvement of impact sound insulation ΔL. The improvement of impact sound insulation of a floating floor is a key parameter for the calculation of structure-borne sound insulation in buildings. Indeed, once ΔL is known, it is possible to evaluate the impact sound insulation, in in situ conditions, for several base floors of different building technologies and materials. ΔL can be directly determined on the basis of standard laboratory measurements, but it can be also estimated from elastic and inertial properties of involved materials, such as stiffness and mass. In this paper a constitutive model for the estimation of floating floors improvement of impact sound insulation is presented. As it will be shown, the constitutive model proposed based on force transmissibility theory, allows to accurately estimate the acoustical behavior of a floating floor, as a function of frequency, with a simple single function. Theoretical assumptions, experimental evidences and comparisons with previous computational models (e.g., Cremer-Vér model) allow to confirm both validity and effectiveness of the proposed model.

Apparent sound insulation in cross-laminated timber buildings

With the 2015 National Building Code now in effect in Canada, predicting the apparent sound insulation in buildings from laboratory measurements is becoming increasingly relevant for architects and designers. In North America, the apparent sound insulation is classified in terms of Apparent Sound Transmission Class (ASTC). The ASTC rating includes both the transmission through the separating assembly and the transmission via flanking paths. The National Research Council Canada has published a number of guideline documents that detail the calculation procedure for ASTC and provide the required laboratory data for various construction types. In NRC Research Report RR-335, “Apparent Sound Insulation in Cross-Laminated Timber Buildings” the focus is on buildings which are constructed from cross-laminated timber (CLT) panels. Measurements of the direct sound insulation of CLT panels and the vibration attenuation at their junctions were conducted at the NRC in recent years. The report RR-335 describes how to combine the relevant data to obtain estimates of the apparent transmission loss and the ASTC rating for a given CLT construction. This presentation will present highlights of the report and demonstrate the use of the Simplified Method and the Detailed Method to calculate the ASTC rating.

A strategy for sustainable acoustic classification scheme of dwellings

The new legislation in Serbia for sound insulation in buildings, currently in preparation, should introduce for the first time a national implementation of dwellings’ acoustic classification. There are some structural systems and building typology that are common in existing housing stock. Some of them are caused by seismic demands and some by architects’ routines. All that introduced realistically accessible range of apparent sound reduction index values at different positions in existing buildings. To achieve a sustainable classification scheme in prepared new legislation the analysis of sound insulation in existing buildings were performed and implications of possible boundary values between different classes on the housing stock acoustic score were analyzed. Based on such approach, the suggestions concerned with the classification scheme and class limits are presented.

Test and rating method comparison between Japan and the U.S. for airborne sound insulation in buildings

The Japanese test methods for laboratory measurement of airborne sound transmission loss for building partitions are basically the same as the American test methods. However, the two countries’ field test methods for airborne sound insulation in buildings differ. The octave band sound pressure level difference between two rooms is the most significant value for the field evaluation of sound insulation in Japan, whereas the apparent transmission loss for a partition installed in a building is the most popular value for the field evaluation of sound insulation in the US. Why is the octave band sound pressure level difference popular in Japan? It is the basic way of thinking in Japan that an acoustical engineer should take responsibility for the total spatial sound insulation performance, including sound absorption and flanking transmission from the design stage to completion and the field test and evaluation method as the completion inspection should be simple. If the insulation performance does not meet th...