Sound Insulation In Buildings Research Articles

Effect of room partitions on airborne and impact sound insulation in large, open rooms

ISO 16283 for measuring sound insulation in buildings supersedes ISO 140 but is particularly lacking for measurements in large, open rooms of the type considered here (floor volume: ~4000 m3). Following ISO 16283-1, the room volume is theoretically divided into smaller volumes through an analysis of sound level distribution. Large absorbing panels in the ceiling prevent the growth of diffuse sound fields, and thus, the analysis makes critical use of normalization factors used in the airborne sound insulation and impact noise levels based on the Sabine equation. Given the likely division of finished floors into rooms, mobile separation walls are used here to investigate the influence of partitions on sound insulation. The results seem to show that they reduce sound insulation and increase impact noise level in each considered enclosed volume. These variations were investigated further through measurements taken in two volumes of different dimensions and at positions near to and far away from the separation walls.

Performance of Sound Insulation in Buildings - A Case Study

Performance of Sound Insulation in Buildings - A Case Study

Auralization of sound insulation in buildings

In various surveys, it was found that people living in multi-family dwellings and apartment houses are annoyed by noise of their neighbors. Also, it seems that building regulations, for example, the German standard DIN 4109 “Sound insulation in buildings,” are insufficient. The degree of annoyance is influenced by the personal conditions of the habitants (stress), the value of the dwelling and the duration the habitants live there. The effects on humans include disturbance of conversation or listening to the TV or radio in private dwellings as well as communication in office premises, reduced power of concentration during physical or mental work, and disturbance of sleep. All this strongly depends on the kind of noise signal (speech, music, footfall, etc.) and on the context, and thus, it is highly doubtful if single-number quantities such as the STL sufficiently describe the real situation. In this paper, a technique is presented for auralization of complex virtual acoustic scenes including airborne and structure-borne noise in buildings with particular respect to sound propagation across or between coupled rooms. Based on SEA-like sound propagation models in standardized prediction methods (EN 12354), algorithms are designed for FIR filtering of audio signals and applied in listening tests and for to creation of audio demos. The auralized sounds can be used during building design processes, in studies of human noise perception, and in development of new metrics for future building codes.

State of field measurement of facade sound insulation in buildings: evaluation of proficiency testing data according to ISO 140-5:1998

The ISO 140-5:1998 standard specifies the testing methods to evaluate the sound insulation in buildings and building elements for facades. Three rounds of a proficiency testing scheme for airborne sound insulation measurements have been performed according to the methods specified in the standard for a whole facade by using an external loudspeaker as the noise source. The adequacy of the intercomparison is guaranteed by means of the assessment of global precision criteria in compliance with the scope stipulated by the normative references in order to determine the reproducibility limits in a regulated measurement method. To evaluate the participant performance, the corresponding combined scores as composite indexes are calculated, so if this assessment is performed along a certain number of rounds, it will remark the participants that show an overall satisfactory performance by monitoring their achievement over time. Therefore, in order to establish a reference value in terms of precision level, an approach based on the development of a collaborative test in controlled conditions is proposed. The goal is to provide reliable and updated criteria for the evaluation of repeatability and reproducibility limits in this field, particularly in those scopes in which nowadays there is no normative reference or this is very poor. Furthermore, these prescribed values of precision should be verified regularly, as well as the definition of practical conditions of application.

Uncertainty of façade sound insulation in buildings by a Round Robin Test

The uncertainty of field measurements of a façade was evaluated by a Round Robin Test (RRT) conducted in a full-scale experimental building at the Construction Technologies Institute of the National Research Council of Italy (ITC-CNR). Each of the 9 teams involved in the RRT replicated the tests 5 times, for a total of 45 measurements, while reverberation time was repeated 110 times. Both for façade sound insulation and reverberation time the main variations in the one-third octave bands were found in the low frequencies range. The study was also focused on the evaluation of single number quantities (SNQs) and their uncertainties. Single number quantities were evaluated in both narrow (from 100 to 3150Hz) and extended (from 50 to 5000Hz) range. Concerning the SNQs and their uncertainties, no significant differences were observed whether the low frequencies were included or not, unlike the case of airborne sound insulation (investigated in the first part of this study). The uncertainty results were compared with the relevant standards and with literature results. Based on these comparisons, it was highlighted that the standard deviation of reproducibility of façade elements is not adequately reflected in the ISO 12999-1 and further research is needed to specify the in situ standard deviation of reproducibility for façade elements.

Factors affecting the sound insulation in the prefabricated buildings

The sound insulation in buildings is affected by many factors related to various sound transmission paths between rooms. Among them the following paths can be distinguished: the so called direct path dependent on the sound insulation of the partition between rooms, the structural flanking transmission paths and additional airborne paths due to sound transmission though leaks and ducts linking the rooms (e.g. ventilation ducts). The paper analyzes the influence of these factors on sound insulation in multifamily, prefabricates buildings. Laboratory and field measurement results made by ITB’s Acoustic Department in the period of 1975-85 are presented.

Field Measurements of Sound Insulation in Large, Open Rooms

The international standards governing the measurement of sound insulation in buildings (ISO 140) do not explicitly cover the methodology of taking measurements in large open rooms. A building with open plan floors, each of about 1300 m2, is considered here. The ISO 140-14 standard, through an analysis of sound level distribution, allowed smaller partitions to be identified and used as reference volumes. Different index calculation methods allowed critical issues to be highlighted. The impact sound index was strongly affected by geometry (i.e., volume); therefore, its calculation using different virtual volumes gave differing results. Furthermore, the index calculated using the logarithmic average of the indices for each virtual volume and an extended analysis of measurements over the entire floor provided different results. The airborne sound insulation index was demonstrated to be independent of the choice of virtual volumes; it could be consistently calculated using either the logarithmic average or the extended analysis.

On the suitability of ISO 16717-1 reference spectra for rating airborne sound insulation

A standard proposal for rating airborne sound insulation in buildings [ISO 16717-1 (2012)] defines the reference noise spectra. Since their shapes influence the calculated values of single-number descriptors, reference spectra should approximate well typical noise spectra in buildings. There is, however, very little data in the existing literature on a typical noise spectrum in dwellings. A spectral analysis of common noise sources in dwellings is presented in this paper, as a result of an extensive monitoring of various noisy household activities. Apart from music with strong bass content, the proposed "living" reference spectrum overestimates noise levels at low frequencies.

Uncertainty analysis by a Round Robin Test of field measurements of sound insulation in buildings: Single numbers and low frequency bands evaluation - Airborne sound insulation

The uncertainty of field measurements of a lightweight wall and a heavy floor was analysed by Round Robin Test (RRT), conducted in a full-scale experimental building at ITC-CNR. Each of the 9 teams involved in the I-RRT replicates the tests 5 times, for a total of 45 measurements, while the repetitions of reverberation time were 110. Both for sound insulation and reverberation time the main variations are in the low frequency range. The differences between D, R', Dn and DnT and their reproducibility and repeatability standard deviations values were also analysed. The study is also focused on the single numbers evaluation: true value and uncertainty. Single numbers were evaluated in both narrow and extended range. The extension to low frequencies implies a variation in single number values that reaches its maximum in the case of X +Ctr in the extended range. This is because this index is the most influenced by low frequencies. Thus the measurement uncertainty at low frequencies has to be more deeply investigated, before including the low frequency range in the on-field measurements

Calculation of sound insulation of airborne noise of indirect action

The overview of the main methods for calculating flanking airborne noise , and the value of flanking noise under the problem of determining the overall sound insulation of buildings are given in these materials. The results are presented in the form of basic formulas allow to quantify the flanking sound insulation on noise levels in adjacent areas.

Sound insulation design by using noise maps

The EU Directive 49 urges countries to prepare the strategic noise maps and the action plans for the agglomerations along major transportation routes and major industrial premises. Environmental engineers, town planners and architects are involved in preparation of action plans in which sound insulation of buildings are to be considered. This article describes a model to determine the required insulation performances for buildings’ external elements by using strategic noise maps. The model employs certain categorization for buildings in relation to indoor noise criteria and for insulation values to be assigned on building facades. A calculation procedure is integrated with the outputs of a noise mapping software to obtain the required noise reduction indexes in terms of both spectral values and the single-number ratings, i.e. “weighted- standardized level differences”. Calculated results are displayed graphically to be able to observe variation of insulation requirement throughout the surface exposed to noise source. Insulation map as a visual tool can facilitate building noise control and can be utilized in preparation of building specifications prior to construction phase and in developing the insulation codes by local administrations. Implementation of the model for two sample buildings located at different environments are explained in the article.

Sound Insulation in Buildings

Sound Insulation in Buildings

Uncertainty of measured and calculated sound insulation in buildings - Results of a Round Robin Test

An inter-laboratory comparison has been made in situ with the participation of 8 laboratories. The operators measured airborne and impact sound insulation of 7 partitions according to the ISO 140 standards and some additional guidelines. Variations of sound insulation, and their components, have been analyzed. In addition, field measurements of sound insulation in 40 building cases were compared to calculations according to EN 12354 (-1, -2). Safety margins for predictions of 3 dB are recommended for calculation of heavy building partitions, with respect to an estimated risk of 5% being disapproved by a sample measurement in situ.

A standard way of measuring rainfall noise

About 10 years ago at an ISO TC 29 meeting, the concept of the measurement of rainfall noise was suggested. At the time it made no sense to me. Who cares about this? Not me, since I liked the sound of rain on my roof, and the louder the better. The concept was to evaluate roofs to assess the insulation capabilities from sound (vibration?) produced by rainfall. But in spite of my skepticism, wiser heads prevailed, and in the end, the approach was drafted into a work item, a draft, and a final draft standard. This paper is a summary of ISO FDIS 140‐18, ‘‘Acoustics—Measurement of sound insulation in buildings and of building elements—part 18: Laboratory measurement of sound generated by rainfall on building elements.’’ I discuss the equipment needed, the test method, and the uncertainty.

Japanese standards and situation of studies about heavy and soft impact sources

This report describes standards of heavy and soft impact sources. They are used for measurement of floor impact sound insulation of buildings. In Japan, the method for field measurement of floor impact sound level (JIS A 1418) was revised in 2000 and separated into two parts. Part 1 uses a standard light impact source and corresponds to ISO 140‐7. Part 2 uses heavy and soft impact sources. At that time, a rubber ball was standardized along with a car‐tire source in JIS A 1418‐2. Moreover, JIS A 1440‐1 and JIS A 1440‐2 for laboratory measurement of the reduction of transmitted floor impact sound have been prepared. JIS A 1440‐1 corresponds to ISO 140‐8, and JIS A 1440‐2 uses heavy and soft impact sources. Floor impact sources characteristics are introduced. They include force characteristics, temperature dependence, stability, and others. In addition, among contents of JIS A 1440‐2, the measurement method, calculation method, and a laboratory of a box‐frame‐type reinforced concrete construction are explained. In addition, study examples using a rubber ball are introduced. As examples, we present the floor impact sound level, the transmitted floor impact sound level, hearing tests on floor impact sound, and evaluation of walking sensations.

VIBRATION TRANSMISSION THROUGH JOINTS OF WALLS AND COLUMNS IN FRAMED BUILDINGS

Constructional practice has shown that structure‐borne sound transmission through joints can signally reduce airborne sound insulation in buildings. Vibration transmission coefficient evaluates this reduction in design calculations. In this article sound transmission through joints in framed buildings is investigated. Rooms in framed buildings are shaped by walls and ceilings connected to columns. Several walls could be connected to each column in a building plan. Such joints are modelled like idealised plate–beam–plate junctions. Examining vibration transmission through these junctions, the influence of a column must be estimated. The column will resist forces and moments applied by the connected walls. The aim of the paper is to evaluate how various properties of walls and columns influence the vibration transmission loss at joints of buildings. The results are compared with the results of similar junctions without columns.

Vibration transmission through joints of walls and columns in framed buildings

Abstract Constructional practice has shown that structure‐borne sound transmission through joints can signally reduce airborne sound insulation in buildings. Vibration transmission coefficient evaluates this reduction in design calculations. In this article sound transmission through joints in framed buildings is investigated. Rooms in framed buildings are shaped by walls and ceilings connected to columns. Several walls could be connected to each column in a building plan. Such joints are modelled like idealised plate–beam–plate junctions. Examining vibration transmission through these junctions, the influence of a column must be estimated. The column will resist forces and moments applied by the connected walls. The aim of the paper is to evaluate how various properties of walls and columns influence the vibration transmission loss at joints of buildings. The results are compared with the results of similar junctions without columns.

Case Study: Laboratory and Field Measurements for Evaluating the Weighted Reduction in Impact Noise Associated with Floor Coverings

In order that impact sound insulation in buildings complies with national regulations, the use of floor coverings needs to be considered, either at the design stage, or as a corrective measure. The improvement of impact sound insulation for floor coverings shown in marketing literature, comes from laboratory tests, expressed as the difference between the values of bare and covered floor noise insulation indices, calculated in accordance with what is prescribed in standard EN ISO 717/2. However, the values of the improvement for the same product are sometimes very different from laboratory to on-site conditions. This problem is more acute for buildings with non-homogenous floors such as beam-block. This case study presents some tests performed on identical horizontal beam-block slabs, in the laboratory and on site, using the same floor coverings. Discrepancies in the values obtained for the characterisation of each floor covering are observed. Assuming that part of the problem could be linked to the type of index used, a comparison is made using the following metrics: ΔdB(A); ΔLn,w (or ΔL3n,w – when on site); and the difference of Loudness Level.

Can Beam-Block Floors Be Considered Homogeneous Panels regarding Impact Sound Insulation?

This paper presents a study of the acoustic performance of beam-block floors regarding impact noise, modelling them as homogenous floors with the same mass per unit area and same elastic characteristics. The study mainly consisted in the development of a simplified analytical model to characterise impact sound insulation in buildings, according to what is established in the appropriate set of international standards, and in its validation with experimental results. The study was developed under two main lines of investigation: experimental work carried out in laboratory facilities; and the evaluation of the efficiency of the analytical model. The model is based on two methodologies: the modal approach and statistical energy analysis (SEA). The first one applies to the low frequency range and the second one to high frequencies.

木造集合住宅の遮音性能に関する研究者・技術者へのアンケート調査結果

We executed an questionnaire survey inquiring about engineering level on sound insulation of walls and floors of wooden apartment buildings recently built in Japan. (This questionnaire, however, was practically executed in 1994.) Answerers were Japanese researchers and engineers whose specialty was sound insulation of buildings. In this paper, we introduce the results of this questionnaire and give our opinion about sound insulation performance of walls and floors of wooden apartment buildings.