Sound Insulation Tests Research Articles

Analysis of the effects of uneven sound coverage over a facade during a sound insulation test according to the international standard ISO 16283-3

Building regulations worldwide include specific sections on protection against noise and vibrations, making sound insulation of facades an important part of regulations in many countries. Consequently, sound insulation field tests become important, as a way to certify, or check, if a facade complies with the regulatory requirements. The international standard ISO 16283-3:2016 specifies the procedures and methods to describe the sound insulation of a facade, making the loudspeaker method for the whole facade one of the most widely used because of the advantages it has for practitioners.To make the method consistent, the international standard establishes some constraints, trying to minimize the variation of sound pressure level on the facade. This variation is caused by the directivity of the loudspeaker and the distance from the loudspeaker to the facade, causing an uneven sound coverage over the facade. This paper analyzes and quantifies the solitary influence of facade coverage on the sound insulation determinations in relation to the location of the facade elements. In addition to other influences, the specific location of a small air inlet on a facade can alter the results by up to 4dB, even if the sound coverage complies with the requirements established by the international standard. Finally, an alternative measurement setup is discussed that aims to minimize the negative effect of this phenomenon in an attempt to increase the consistency of the method.

Retrofitting masonry and cavity brick façades for different noise zones using laboratory measurements

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.

Historical building acoustical retrofit: An experimental examination of traditional wooden floors

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 ([Formula: see text]) 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.

나노필라멘트 직물의 열 및 음향학적 특성에 관한 연구

Nanofibers, which have larger specific surface areas than conventional fibers, significantly enhance the functionality of conventional fiber materials in addition to introducing new features. Thermal barrier and sound insulation tests were conducted to assess the thermal and acoustic properties of the nanofilament fabrics prepared from polyethylene terephthalate (PET)/modified PET sea-island bicomponent fibers. The results indicate that fabrics with filament diameter of 400 nm exhibited excellent thermal and sound insulation performance compared to the fabrics with filament diameter of 600 nm.

Implementation of a virtual laboratory for training on sound insulation testing and uncertainty calculations in acoustic tests.

This paper describes a methodology and case study for the implementation of educational virtual laboratories for practice training on acoustic tests according to international standards. The objectives of this activity are (a) to help the students understand and apply the procedures described in the standards and (b) to familiarize the students with the uncertainty in measurement and its estimation in acoustics. The virtual laboratory will not focus on the handling and set-up of real acoustic equipment but rather on procedures and uncertainty. The case study focuses on the application of the virtual laboratory for facade sound insulation tests according to ISO 140-5:1998 (International Organization for Standardization, Geneva, Switzerland, 1998), and the paper describes the causal and stochastic models and the constraints applied in the virtual environment under consideration. With a simple user interface, the laboratory will provide measurement data that the students will have to process to report the insulation results that must converge with the "virtual true values" in the laboratory. The main advantage of the virtual laboratory is derived from the customization of factors in which the student will be instructed or examined (for instance, background noise correction, the detection of sporadic corrupted observations, and the effect of instrument precision).

Influence of low frequency bands on airborne and impact sound insulation single numbers for typical Portuguese buildings

This paper presents an analysis of in situ measurements for airborne and impact sound insulation performed in typical buildings in Portugal. The direct partition element separating rooms consists of different types of walls or floors. The buildings have concrete frame structures and the partitions are, in the main, heavy walls or floors. A number of group of lightweight walls were studied.The next revision of ISO 717 provides for the inclusion of low frequency bands in the calculation of the sound insulation descriptors and so the aim of this work is to ascertain the influence of the low frequency band measurements on the descriptor results for typical buildings in Portugal. The descriptors (single numbers) for airborne sound insulation DnT,w, DnT,w+C, DnT,w+C50–5000, DnT,w+Ctr and DnT,w+Ctr,50–5000 were calculated and analysed. The impact sound insulation descriptors calculated and studied are L′nT,w, L′nT,w+CI and L′nT,w+CI,50–2500. Additional calculations were performed to determine the uncertainty of the descriptors analysed.The airborne sound insulation tests were performed according to NP EN ISO 140-4 in one-third octave bands from 50Hz to 5000Hz. The impact sound insulation tests followed the procedure set out in NP EN ISO 140-7 with measurements in one-third octave bands from 50Hz to 5000Hz.

Sound Insulation Properties of Abandoned Fibers Composites

In this article, in order to study the sound insulation properties, abandoned cotton and jute fibers were conducted as reinforced materials, TPU and PP were conducted as matrix materials, and double roller mixing and hot pressing molding processes were adopted to prepare composites. Through the L12 (42×13) mixed orthogonal experiment, cotton/TPU, cotton/PP, jute/TPU and jute/PP composites were prepared respectively. Standing wave tube and impedance tube’s sound absorbing and insulation test system which was produced by Beijing Prestige Company were employed to test the sound insulation (transmission loss). And they were used origin software to analyze. Universal mechanical testing machine and Jane suspension combined impact tester were employed to test tensile, bending and impact strength of jute/TPU composites. Results were showed that four kinds of composites had excellent sound insulation properties. And the jute/TPU composite was the most optimal. Under the conditions of thickness in 6 mm and frequency at 6300Hz, transmission loss of jute/TPU composites was up to 30 dB and it had excellent mechanical properties.

Straw bale sound insulation: Blowing away the chaff

Popular opinion states that straw bale walls are good at isolating sound. Cheap load bearing straw bale houses could contribute substantially to low carbon sustainable construction. However, literature on the subject was found to be highly anecdotal. The paper presents a summary of nine laboratory and field sound insulation test reports and two especially commissioned tests. Data were compared to European party wall sound insulation criteria, and it was found that straw walls could perform as well as, but sometimes worse than, conventional constructions, due to poor performance at low frequencies. Better performance could help to promote the use of straw bales in multi-unit housing. It was found that by adding a plasterboard layer on studs to just one side of a plastered straw bale wall would allow the construction to pass all of the criteria reviewed.

Evaluation of Sound Insulation Performance of Extruded Cement Panel with a-Hemihydrate Gypsum

The extruded cement panel, which has many advantages as a prefabricated method, has been limited in its application due to its low fire-resistance. However, an extruded cement panel produced by mixing a-hemihydrate gypsum offers dramatically improved fire-resistance and is expected to have wide-ranging applications in the construction sector as an interior material or partition wall between housing units. Sound insulation performance is very important for the partition wall between housing units. In this study, the sound insulation performance of the extruded cement panel produced through the mixture of a-hemihydrate gypsum is reviewed in order to determine its usability for a partition wall between housing units and for interior materials. Through the review it was found that the wall formed using the extruded cement panels produced by mixing the a-hemihydrate gypsum have ★★★ class in sound insulation test, equal or superior compared with the other two types of extruded cement panel walls currently available in the market.

Impact sound insulation technique using corn cob particleboard

A low technological corn cob particleboard has been under research by this research team. It intends to be affordable and sustainable. So far, some of its assessed material properties (e.g. density, fire resistance, durability, thermal conductivity, compression and bending strengths, and impact resistance) suggest adequacy of this product for several building applications, such as a thermal insulation product, a light weight partition wall, a ceiling coating, or as indoor doors, among other possibilities. However, proper acoustic insulation performance is also a fundamental property required for most of the above identified building applications. Therefore, this paper is focused on evaluating the impact sound insulation potential of the proposed particleboard. At this stage, impact sound insulation tests have been performed in which the acoustic insulation gain of a pavement reinforced acoustically by a 3cm thick corn cob particleboard was assessed. The obtained acoustic insulation gain was then compared with the respective ones of traditional sound insulation products (e.g. glass wool and expanded polystyrene) and also with different alternative natural sound insulation products (e.g. kenaf, coco fibre, sheep wool, cork and cellulose). The obtained results indicate that the proposed product may also have an interesting acoustic behaviour for building purposes. This conclusion is even more interesting taking into account that corn cob is a natural, organic, renewable and local raw building material.

G100043 窓ガラスの音響特性に関する研究

This study is intended the improvement of the performance on the window glazing. The key performance of the window glazing is to obtain the acoustic characteristic for the quiet environment. We perform sound insulation tests in order to obtain the acoustic properties of the window glazing and to calculate the sound transmission loss. The vibration measurements to synthesize damping coefficients of modes are also executed. On the other hand, the analysis model is constructed for the acoustic insulation characteristic by using of 3D-CAD system. Acoustic analysises have been executed by both the finite element method and the boundary element method. We evaluated the relation between the actual measured values and the analysis results. The main factor for sound transmission through the window glazing to realize the improvement of the insulation performance is considered in this report.

장수명 주택의 활성화를 위한 가동칸막이벽체 개발현황 연구

The purpose of this study is to develop the feasibility of movable partition wall components that are able to correspond changes of structure system and spatial configuration by the needs of residents for the activation of long-life housing. The key element of various movable partition wall components, a movable partition wall, was analyzed for problems through both as-is analysis and field installation in Korea and Japan, and then its feasibility was verified. The movable partition wall can break the uniformity of a fixed one, can integrate and separate limited space by changes in the demands of residents, can be easy to separate, and can be independent. The development of the movable partition wall is important for the realization of diverse residential space, ease of remodeling, environment adaptation, promotion of modularization, etc. It is comprised of surfacing materials, core materials, structural materials, and movable parts. The domestic movable partition wall was verified regarding the feasibility of an apartment house through on-site inspections and sound insulation tests by KOHP21, KICT. In conclusion, the construction of long-life housing that has sustainable values in the use of housing is nationally an important assignment, so as to secure good housing stock.

Mechanical Properties and Sound Insulation Effect of ABS/Carbon-black Composites

This article describes an evaluation of the mechanical properties and sound insulation effects of composites made of acrylonitrile butadiene styrene (ABS) and carbon-black using the design of experiment (DOE) approach. The solution blending process and method are presented. The effect of the acetone content in ABS during the drying process was studied by conducting tensile tests of injection-molded specimens. ABS was dissolved in acetone, and carbon-black was dispersed in the ABS/acetone mixture with varying conditions according to the orthogonal array table used to reduce similar experiments. The tensile specimens were produced by injection molding in each of the DOE cases, and the elastic modulus and maximum tensile strength of ABS/carbon-black composites were evaluated with a tensile test to determine the main effects of those factors. A sound insulation test was conducted with a modified impedance tube by using the DOE orthogonal array table, and a correlation between carbon-black and the sound insulation was revealed by a main effect analysis. An additional sound insulation test was conducted to verify the sound insulation effect of ABS/carbon-black composites as a function of the carbon-black percentage. The results indicate that the increase of carbon-black affected the mechanical properties as well as the sound insulation effects of ABS/carbon-black composite.

Measurement uncertainties caused by tapping machines in floor sound insulation tests.

This paper illustrates how the parameters of the tapping machine may influence the measurement accuracy when testing the impact sound insulation of floors. The analysis connects the specifications for tapping machines given in ISO 140‐6 and ASTM E 492‐4 standards with the requirements for repeatability and reproducibility of the sound insulation measurements given in ISO 140‐2. The paper also discusses calibration and testability aspects for tapping machines and presents the method developed at Scantek for measuring the impact velocity of the hammers. The paper gives modeling equations, preliminary calculations for measurement uncertainties, and experimental results obtained at Scantek on calibrating the Norsonic tapping machine N‐211.

Quantitative evaluation of airborne sound insulation in ship’s accommodation using large scale noise test facilities

In recent years, the regulation on the airborne sound insulation index has become much more stringent as the increasing demand on the building of low noise vessels. So, some studies have been performed to improve the sound insulation in accommodation spaces. So far, however, the improvement has not been clearly obtained due to the complicated coupling relation between acoustic elements. In this paper, the onboard sound insulation tests for ship's accommodation spaces were firstly carried out to investigate the acoustic characteristics. Secondly, by using two reverberation rooms and a deckhouse mock-up having the same characteristics as a real ship, the sound transmission loss of cabin structures, such as ceiling, door, floor, and partition wall, were quantitatively evaluated and compared with in-situ test results. Through a series of tests, it was found that the airborne sound insulation in a ship's accommodation was greatly deteriorated by the door and the partition wall. The main acoustical effects dominating the flanking sound transmission in adjacent accommodation spaces were fully identified.

Issues in acoustic field testing of quiet modular classrooms

Modular classrooms are important to American education: About 300,000 modular classrooms are currently in use by public school systems here. Good acoustical conditions for learning are no less vital for students in modular classrooms than stick-built classrooms. In an effort to promote good acoustics in modular classrooms, ANSI S12 Working Group 46 is seeking to standardize acoustic field testing. Their efforts are in response to key acoustical issues of modular classrooms: Excessive noise from HVAC (heating ventilating and air conditioning) systems, and poor airborne sound insulation from exterior noise sources. In a recent and notable advance, an HVAC system provider reported good progress in modular HVAC noise reduction: A ducted wall mounted system was used instead of the usual free blowing system with exposed fans. HVAC noise in the unoccupied room was near the maximum 35 dB level required by ANSI S12.60. Interior noise levels were so low that efforts to confirm their values were confounded by noise contamination from exterior sources. The relatively high interior ambient noise levels were due to poor airborne sound insulation. Lessons learned from recent field testing will be discussed. Results of airborne sound insulation tests, now in planning stages, will be reported if available.

Sound Measurements and Natural Ventilation in Schools

Natural ventilation using open windows is an energy efficient and effective method of providing a good indoor air climate in schools. However, open windows not only let fresh air into the building but also external noise. The availability of automatically controlled windows enables precise control over the window opening distance in comparison with manually operable windows. This paper considers the benefits of using small opening distances to provide sufficient ventilation for a good indoor climate as well as attenuation of external noise. Airborne sound insulation tests on a window with different opening distances show that the sound insulation varies significantly depending upon the opening distance; the smaller the opening distance, the higher the sound insulation. In many cases, an opening distance as small as 1 to 2 cm can not only provide sufficient ventilation for a good indoor climate, but also adequate sound insulation. The results of sound attenuation tests, performed at BRE in the United Kingdom, are presented in this paper. In addition, empirical results from 3 different naturally ventilated schools, including two in Denmark and one in the UK are described. These results indicate that often only small opening distances are required to obtain a comfortable thermal and atmospheric indoor climate based on measurements during the year.

Determination of sound reduction indices in the presence of flanking transmission

Unlike the standard sound insulation test method, which requires diffuse sound fields in both source room and receiving room, the sound intensity method only requires the source room to be diffuse. Flanking may, in some cases, cause large errors in the sound reduction indices obtained by the standard method, even if the flanking power is measured separately and subtracted from the total power. The sound intensity method allows selective determination of sound reduction indices for test objects surrounded by flanking surfaces, provided the measurement surface in the receiving room is defined in such a way that it encloses nothing but the test object.

The field performance of partially open dual glazing

The insulation of partially open dual glazing has already been measured in the laboratory. During an extensive programme of sound insulation tests on a house near Manchester Airport the opportunity was taken to measure the field performance. The results show an increase in insulation of up to 3 dB(A) when compared with predictions based upon laboratory SRIs. An assessment was also made of the ventilation by comparing the rate of air change when the dual windows were open with that due to a mechanical ventilator operating with the windows closed. Under typical weather conditions it was found that there was little difference, a rate of 2–3 air changes/hour being measured.