Impact Sound Reduction Research Articles

Impact sound insulation performance of floor coverings in a heavyweight reference floor with a floating floor

This study investigates the impact sound reduction performance of floor coverings used on the heavyweight standard floor of a floating floor structure in comparison with bare slab testbeds through on-site experiments. The laboratory performance evaluation of floor coverings designates only a bare slab between 100 mm and 160 mm as the heavyweight reference floor according to Annex C in ISO 10140-5. However, the recent expansion of over-floor heating systems has led to an increased need for understanding the impact sound reduction performance of floor coverings on floating floors, to enhance occupants' thermal comfort. In this study, it was measured the heavyweight and lightweight floor impact sound reduction levels of various floor covering test specimens in testbeds with different thicknesses of bare slabs and actual apartment houses with floating floors applied. The reduction rate for each frequency band was determined before and after installing floor coverings including single number quantity in accordance with ISO 717-2. Additionally, the impact of heavyweight reference floor conditions on quantifying the sound performance of floor coverings was discussed.

Impact Sound Reduction Performances of Additional Floor Mats for the Retrofitting of an Existing Apartment Building in Accordance with Test-Bed Conditions

Floor mats are commonly used to improve the impact sound performance of existing homes, but actual impact sound reductions do not consistently appear, as they depend on the test-bed conditions used to determine impact sound performance. Therefore, this study evaluated the effects of the environmental conditions of the test bed on the impact sound reduction performances of different floor mats. The Korean industrial standard KS F 2865 specifies the measurement method in the test room and sets the thickness range of the available target floor structure to bare slabs with thicknesses ranging from 120 mm to 210 mm. The evaluation method is ∆L, which is the difference in standardized impact sound levels before and after the installation of the floor finishing material. In this study, a total of eight types of floor mats were tested in four different test beds according to KS F 2865. The impact sources used were tapping, bang machines, and a rubber ball, and we used these sources to consider both light-weight and heavy-weight impact sounds. The results were derived as the impact sound reduction performance for each frequency band and a single-number quantity. The results showed that light impact sound had a similar minimum reduction characteristic of at least 38 dB, regardless of the floor structure on which the mat was installed. However, the heavy-weight impact sound showed different tendencies depending on the floor mat and the characteristics of the floor structure of the test bed when a bang machine and a rubber ball were used. In particular, the reduction achieved by the bang machine showed less than half the tendency of the reduction by the rubber ball, and the tendency of the heavy-weight impact sound was shown to be reducible depending on how the floor mat was maintained, but the reductions differed depending on the test bed. The reductions were larger in the box-type test room than in the real-life-type test room, and among the box-type test rooms, the one with a thicker bare slab showed a relatively larger reduction. In addition, the reliability of the measurement results was evaluated through a correlation analysis between the single-number quantities depending on the thicknesses of the bare slabs of the test beds.

A study on the evaluation of impact sound reduction performance of floor mats for reducing floor impact sound in apartment buildings

This is a study on the performance evaluation of floor mats used to reduce floor impact sound in apartment houses in South of Korea. A total of 8 types of floor mats and 5 or more test rooms with different floor structures were used to measure and evaluate impact sound reduction performance. The impact source is a Bang machine (heavy-weight impact sound 1), a rubber ball (drop of height 100 cmHeavy-weight impact sound 2) tapping machine (light-weight impact sound), and a rubber ball drop height of 40cm that simulates the actual impact force. As a result of the test, the impact sound reduction performance for the light-weight impact sound was evaluated as excellent. It was evaluated at the level of ambient background noise. Also, the reduction performance of the bang machine was somewhat different depending on the floor structure. In addition, there are cases where it is rather amplified in the low frequency band (63 Hz). In the case of rubber ball (drop of height 100 cm), the reduction performance was different depending on the floor structure. However, the impact sound reduction performance was evaluated to be sufficiently reduced. The impact noise reduction performance at the rubber ball drop height of 40 cm was found to be slightly higher than that at the drop height of 100 cm.

Floor impact sound reduction and impact absorption performance of floor mat

In Korea, the post evaluation system of floor impact sound performance was implemented in August 2022. Therefore, it is necessary to check the floor impact sound performance after the completion of the apartment. If a floor impact sound performance does not meet the regulation limit, compensationm and follow-up renovations are required. In this study, in order to develop a floor mat that can reduce heavy weight floor impact sound, the floor impact sound reduction performance and impact absorption performance of each condition of the sample were confirmed. Floor impact sound reduction performance was measured using the test methods of KS F 2865 and ISO 10140-3, and impact absorption performance was measured according to the test method of JIS A 6519. As a result of the measurement, the performance of reducing floor impact sound showed a clear difference in performance according to thickness rather than material type. Impact absorption performance was found to be affected by surface hardness and material thickness. In conclusion, it is considered that the selection, thickness, and surface hardness of materials are important design factors when developing floor mats.

Effects of Impact Sound Insulation of Floor Covering on the Properties of Wood Organic Resilient Material

近年來樓板緩衝材多以玻璃棉、橡膠墊或發泡類等工業化之產品為主，在製程或回收利用上亦須依賴大量能源之供應。因此，本研究在地球永續與循環經濟之課題下，以栓皮櫟（Quercus suber）樹種作為研究對象，利用木栓層（Cork layer）組織特性，開發木質有機緩衝材，並搭配複合木地板之面材進行樓板衝擊音隔音性能之探討。研究結果顯示，在栓皮櫟樹皮顆粒使用比例為30 %時，衝擊音降低量預估值達22 dB，較10 %及20 %之比例條件佳，且低頻衝擊音降低量數值較常見之橡膠發泡與PU發泡佳，顯示本研究之木質有機緩衝材除符合生態綠建材之原則外，亦可提升建築樓板之隔音性能。In recent years, glass wool, rubber, and foam were the main materials used in floor resilient material, which consume a lot of energy in the process of recycling. Under the topic of earth sustainability and circular economy, in this study, we took Quercus suber as the research object, and use the organizational characteristics of the Cork layer to develop wood organic resilient material. We discussed the floor impact sound insulation performance of laminate wood flooring and wood organic resilient material. The result showed when using 30 % cork oak, the impact sound reduction value of the floor covering was 22 dB. The impact sound insulation performance of low frequencies of wood organic resilient material was better than rubber and foam. The wood-organic resilient material produced in this study was in line with ecological green building materials and improved the sound insulation performance of building floors.

Impact Sound Insulation of thermally insulated Balconies

With the increasing urban densification, balconies are gaining in popularity as they improve the living quality in homes. Thermal insulation between balconies and the building's façade is state of the art. In Germany the most popular balcony construction is a reinforced concrete balcony, separated from the building by a thermal insulation element (TIE), which is meant to reduce the thermal energy loss and thus ensure the sustainability of buildings. The impact sound transmission from balconies, however, is a problem that has not been addressed enough to date. The main goal of the project is to provide acoustic quantities, e.g., an impact sound reduction, for a TIE that can be used to compare the acoustical quality of products and to predict the impact sound pressure levels within the building using the standard EN ISO 12354-2. Experimental and numerical studies have been carried out on various ceiling-balcony mock-ups without and with TIEs e.g., by means of experimental modal analysis and finite element models. This paper will show the effect that various parameters have on the impact sound insulation. Additionally, the measurements on the test set-up will be compared to measurements on building sites.

Estimation of impact sound reduction by wood flooring installation in a wooden building in Korea

Multi-family homes have been constructed traditionally using heavy materials like concrete/steel and bricks. Wooden structures are a promising substitute for typical heavyweight constructions. However, floor impact noise has been identified as the most annoying noise source in South Korea. Here, we have studied the effect of floorboard installation on impact sound changes before and after installing the floorboard on the floor of a wooden building. We used standard tapping and bang machines in this study to generate lightweight and heavyweight impact sounds. The changes in noise from lightweight and heavyweight impact sounds were estimated on the upper layer (UL) and lower layer (LL) floors before and after the installation of the plywood floorboard (PFB). The average of the octave band center frequencies at 125, 250, 500, 1000, and 2000 Hz from the lightweight impact before installation of PFB was 84.08 dB (UL) and 50.54 dB (LL), respectively, while 84.04 dB (UL) and 41.90 dB (LL) after the installation of the surface decorated PFB. Similarly, the heavyweight impact sound before installing PFB was 73.26 dB (UL) and 42.16 dB (LL), respectively, while after installation of PFB, impact sound appeared at 71.58 dB (UL) and 42.48 dB (LL). The results exhibited that lightweight impact sound could be reduced by about 8.6 dB on the LL. These results could entice the researcher or building engineer to design wooden floorboards for a comfortable building environment. This study is new because it compares the impact sound of the floor before and after it has been constructed.

Effects of Wall-to-Wall Supported Ceilings on Impact Sound Insulation for Use in Residential Buildings

In Korean residential buildings, floor impact sounds were reduced over the past few decades mainly through a floating floor system. However, ceiling constructions for impact sound reduction have not been applied actively because of a lack of useful information. This study focuses on the effects of wall-to-wall supported ceilings (WSC), which are designed with construction discontinuities between concrete slabs and ceilings, and the damping caused by porous absorbers for impact sound insulation. To examine the impact sound insulation according to ceiling conditions, measurements were performed in 25 floor–ceiling assemblies. The results indicate that ceiling treatment is mostly useful in reducing the floor impact sound. The floor impact sound owing to the WSC decreased by 2–7 dB and 2–8 dB in terms of the single number quantity for the tapping machine and rubber balls, respectively, compared with representative existing housing constructions wherein ceilings were attached on wooden sticks. Furthermore, the reduction effect of the WSC appeared to be more profound when it was applied to the floor–ceiling assembly with poor impact sound insulation. Thus, the WSC can be used to enhance the impact of sound insulation of existing housings without major repairs of floor structural layers.

Evaluation of floating floors performances using the reception plate method

This paper concerns the development and experimental validation of a simplified method to evaluate the performances of materials for floating floors. The method is based on the reception plate theory. The porpouse is to evaluate the impact sound pressure level reduction ΔL by the differences of the sound power level ΔP measured on the reception plate with and without the acoustic material. The results are compared with the values measured in accordance with ISO 10140 standards.

Acoustic and thermal performance of sustainable fiber reinforced thermoplastic composite panels for insulation in buildings

Acoustic and thermal insulation are major issues to be considered in buildings' construction to meet the overall comfort conditions indoors and fulfill the energy-efficiency approaches. This work aimed to investigate the acoustic and thermal insulation performance of sustainable thermoplastic sandwich composite panels to be used in floor systems in buildings. Three types of recycled nonwoven fabrics were used in composites reinforcement; jute, polyester and hybrid jute-polyester (80:20%) with polypropylene as the matrix. Compression molding technique was used in manufacturing of the composite panels with different reinforcement and matrix ratios. The acoustic insulation performance of sandwich composite panels was evaluated in terms of impact sound attenuation test. As well the thermal conductivity was determined and the thermal insulation behavior was investigated using infrared thermography. The results indicated that all composite samples showed increased impact sound reduction at low frequencies. Jute and hybrid jute-polyester composites recorded a decrease in impact sounds reduction at high frequencies, whereas polyester composites showed fluctuated behavior. Increasing the reinforcement and matrix ratios enhanced impact sound reduction for jute composites at high frequencies, and for hybrid jute-polyester composites in the mid and high frequencies. The impact sound reduction index ΔLw values of all composites ranged between 12 and 21 dB. Furthermore, samples PJ and PT produced with 1-layer of reinforcement showed the lowest thermal conductivity and higher resistivity values compared to all samples. The polyester composites were the least samples to gain heat temperature after 60 min, and they exhibited the highest temperature difference compared to jute and hybrid jute-polyester composites.

Thermoplastic polyurethane/laponite nanocomposite for reducing impact sound in a floating floor

An effective way to reduce impact sound in buildings is to install a floating floor consisting of a floating slab separated from the structural slab by a continuous viscoelastic layer. Although a considerable amount of work has been reported on nanomaterials in the past decades, the impact sound reduction performance of polymer/clay nanocomposites has not been specifically addressed in the literature. In this paper, we report the synthesis and characterization of a nanocomposite made of thermoplastic polyurethane (TPU) with laponite clay filler and its potential use for reducing impact sound in floating floor technology. Samples were prepared with laponite content ranged between 0.5 and 10 wt% for each nanocomposite synthesized using a solvent solution mixing process. The characterization of the nanocomposites confirmed that the clay content in the TPU matrix has significant impact on the viscoelastic properties. In particular, the incorporation of 5–10 wt% laponite clay in the TPU matrix increased mechanical damping and reduced dynamic stiffness as compared to the pristine TPU. The experimental results were compared with a constitutive model that extends the Cremer-Vér model. The results predicted a considerable improvement of the impact sound insulation at the resonance frequency when the nanocomposite is used as a continuous viscoelastic layer supporting the floating slab. These results were attained without significantly increasing the total weight of the floating layer.

Prediction of the Dynamic Stiffness of Resilient Materials using Artificial Neural Network (ANN) Technique

High-rise residential buildings are constructed in countries with high population density in response to the need to utilize small development areas. As many high-rise buildings are being constructed, issues of floor impact sound tend to occur in buildings. In general, resilient materials are implemented between the slab and the finishing mortar to control the floor impact sound. Various mechanical properties of resilient materials can affect the floor impact sound. To investigate the impact sound reduction capacity, various experimental tests were conducted. The test results show that the floor impact sound reduction capacity has a close relationship with the dynamic stiffness of resilient materials. A total of six different kinds of resilient materials were loaded under four loading conditions. The test results show that loading time, loading, and material properties influence the change in dynamic stiffness. Artificial neural network (ANN) technique was implemented to obtain the responses between the deflection and dynamic stiffness. Three different algorithms were considered in the ANN models and the trained results were analyzed based on the root mean square error. The feasibility of using the ANN technique was verified with a high and consistent level of accuracy.

Evaluation of Floating Floor System with Steady State Dynamics Simulation in the Context of Impact Sound Level

Evaluation of floating floor at the design level imposes to take into account assumption of proper execution of this system, which means assertion of proper localization of dilation. Aim of this research is to analyse usefulness of Steady State Dynamics (SSD) simulation in the context of floating floor performance and execution errors such as global or local lack of circumferential dilatation. For this purpose, two-storey building with one room at each floor was simulated. Floating floor system was applied at structural ceiling between upper and lower floor. Excitation of system was done by application of pressure with given frequencies at central part of floor. Three types of systems were analysed: system without floating floor, system with properly executed floating floor and system with floating floor short-circuited to walls. Application of dynamic bridge was done gradually - at each wall - till whole floating floor was short-circuited. In the result of correlation between akin in-situ test compatible with standards, normative prediction of weighted impact sound reduction index and SSD simulations results was evaluated. Moreover, influence of dynamic short-circuit on floating floor system was analysed. Finally flanking vibration transition between upper and lower room with different systems was discussed. Principal conclusion of performed analysis is fact that SSD simulation results are sufficient to show vibration velocity spectrum nature of changes between systems with and without floating floor. What is more application of dynamic bridges at circumference of floating slab makes given system similar structural ceiling only system, which meets with akin in-situ test in matter of acoustic performance – similar nature of results of impact sound level with and without floating floor. Nevertheless, SSD simulation results are hardly agreeable with normative prediction and in-situ test of weighted impact sound reduction index.

Measurement of in-room impact noise reduction

There are well-established measurement standards for the rating of impact noise reduction provided by floor coverings in relation to structurally transmitted impact noise, e.g. BS EN ISO 10140-3 and ASTM E492 are widely used in Europe and North America Respectively. Standardisation for “in-room” impact noise transmitted by an airborne path is however less well established. At the current time the standard used for rating the “in-room” impact sound reduction is BS EN 16205:2013 which focuses primarily on walking noise as a the impact source. This standard employs the same tapping machine used for impact improvement testing in BS EN ISO 10140-3 but has been found not to be ideal due to the mechanical noise it produces and because it is not fully representative of the walking loads that the standard primarily aims to address. There is currently no standard that deals with “in room” impact noise from falling objects which may be a greater concern than walking noise, for example in a healthcare or education setting. Thus, presented in the paper are the findings from a large measurement survey conducted to investigate the influence of impactor mass, hardness and velocity on measured “in room” impact noise reductions. Other measurands such as the reduction in impact force and floor acceleration are also considered. It is discussed in the paper how ‘In-room’ impact noise differs from transmitted impact noise and this is demonstrated by performing a transfer path analysis to separate out the impact noise contributions from a falling object and from the floor. The key finding of the study is that the whilst the impact noise reduction achieved by different floor coverings varies wildly for different impactor types the rank order of the floor coverings tested in terms of Impact noise reduction did not. Thus, the ideal test method may not be the one that simulates best the type of impacts a floor is likely to be subjected to, but rather, it ought to be the one that gives the biggest differences between similar floor coverings so as to highlight most clearly the differences between them.

Review of acoustic comfort evaluation in dwellings: Part III—airborne sound data associated with subjective responses in laboratory tests

Acoustic comfort has been used in engineering to refer to conditions of low noise levels or annoyance, while current standardized methods for airborne and impact sound reduction are used to assess acoustic comfort in dwellings. However, the results and descriptors acquired from acoustic measurements do not represent the human perception of sound or comfort levels. This article is a review of laboratory studies concerning airborne sound in dwellings. Specifically, this review presents studies that approach acoustic comfort via the association of objective and subjective data in laboratory listening tests, combining airborne sound acoustic data, and subjective ratings. The presented studies are tabulated and evaluated using Bradford Hill’s criteria. Many of them attempt to predict subjective noise annoyance and find the best single number quantity for that reason. The results indicate that subjective response to airborne sound is complicated and varies according to different sound stimuli. It can be associated sufficiently with airborne sound in general but different descriptors relate best to music sounds or speech stimuli. The inclusion of low frequencies down to 50 Hz in the measurements seems to weaken the association of self-reported responses to airborne sound types except for the cases of music stimuli.

An engineering method to measure the impact sound reduction due to soft coverings on heavyweight floors

In order to measure the improvement of impact sound insulation ΔL due to a floor covering in accordance with ISO 10140 standard, a specialised measurement facility is required. As a consequence, such measurements become fairly expensive and available only to those who have access to a specialised laboratory. Therefore, the authors propose an engineering method to measure the ΔL value in the case of soft coverings placed on heavyweight floors. This method enables the replacement of extensive test facilities with one room with a heavyweight floor and a mobile insulation case inside. The inside of the case acts as a source room; the tapping machine and the test sample are placed inside the case, which separates the airborne sounds from the structure borne sounds. The measurement procedure described in ISO 10140 standard is adopted – ΔL is determined by the difference between the sound level outside the case with and without the test sample. In this article, the proposed engineering method is thoroughly delineated and verified with theoretical and energy (SEA) analyses. Next, the results of experimental tests are presented – the reduction of impact sound on four different groups of samples measured in three different rooms. The obtained results are compared with the corresponding ΔL values measured according to ISO 10140 standard. This comparison shows a very strong convergence between the curves of impact sound reduction obtained by both methods. Based on all the above findings, it is stated that the presented engineering method enables accurate measurements of impact sound reduction of heavyweight floors due to soft coverings within the range of uncertainty and application. Due to the reduced measurement facilities in comparison with the ISO standard, the engineering method can be a useful tool in the process of designing and improving products such as soft floor coverings.

Review of acoustic comfort evaluation in dwellings—part I: Associations of acoustic field data to subjective responses from building surveys

Acoustic comfort is a concept hardly described in the literature. But it has been used in engineering typically to refer to low noise or annoyance in order to invoke no discomfort. Current standardized methods for airborne and impact sound reduction are deployed to assess acoustic comfort in dwellings. However, the measured sound pressure levels do not represent comfort. The latter should include further the human perception of the acoustic environment. Therefore, this article reviews studies that approached acoustic comfort through the association of objective and subjective field data, combining in situ acoustic measurements and survey responses from residents. We evaluated the studies using Bradford Hill’s criteria. Most researches focus on self-reported noise annoyance while some others on satisfaction responses. Many studies were found incomprehensibly described: often vital data of statistical evaluation or study design are lacking. The results indicate that noise is a significant issue in living environments, especially certain impact noise types. The use of extended low-frequency spectra down to 50 Hz was suggested for impact measurements in order to predict better self-reported noise response. Greater problems with low-frequency transmission are displayed in lightweight structures which perform inefficiently compared to heavyweight components. Harmonization of presented results and study design details should be taken into account for future articles.

Evaluation Methods of Transmitted Impact Sound Reduction by Floor Covering Materials Using Real Impact Source and Heavy-Weight Impact Sound

Evaluation Methods of Transmitted Impact Sound Reduction by Floor Covering Materials Using Real Impact Source and Heavy-Weight Impact Sound

Prediction on the Enhancement of the Impact Sound Insulation to a Floating Floor with Resilient Interlayer

This paper describes a theoretical method for predicting the improvement of the impact sound insulation to a floating floor with the resilient interlayer. Statistical energy analysis (SEA) model, which is skilful in calculating the floor impact sound, is set up for calculating the reduction in impact sound pressure level in downstairs room. The sound transmission paths which include direct path and flanking paths are analyzed to find the dominant one; the factors that affect impact sound reduction for a floating floor are explored. Then, the impact sound level in downstairs room is determined and comparisons between predicted and measured data are conducted. It is indicated that for the impact sound transmission across a floating floor, the flanking path impact sound level contribute tiny influence on overall sound level in downstairs room, and a floating floor with low stiffness interlayer exhibits favorable sound insulation on direct path. The SEA approach applies to the floating floors with resilient interlayers, which are experimentally verified, provides a guidance in sound insulation design.

Impact sound of timber floors in sustainable buildings

Timber buildings represent a robust alternative to traditional heavyweight constructions. They allow CO2 storage, high structure and performance reproducibility, fast assembly and final certification of every panel.Nowadays, acoustic insulation is one of the most requested performances on the part of inhabitants, but not always fulfilled. Since these kind of edifices are relatively new in the market, there are very few studies on acoustic properties, regarding on impact sound performances. In this paper, an in-depth analysis of impact noise on bare timber floors is presented, focusing on how impact sound reduction cannot be as efficient as in heavyweight constructions. Two new equations are proposed, modelling the impact sound pressure level of common bare timber structures and the influence of traditional floating floor systems is analysed.