Floor Impact Sound Research Articles

Floor impact sound insulation performance of Korean domestic cross-laminated timber floors and the influence of resilient materials' dynamic stiffness

In this study, the floor impact sound insulation performance of floors made of korean domestic cross-laminated timber panels and with a resilient layer under concrete topping was evaluated. The properties of resilient materials used in the floors were measured to evaluate their influence on floor impact sound insulation performance. The results indicate that the highest reduction levels were provided by glass fiber, expanded polystyrene and wood fiber, in diminishing order, for both heavy-weight and light-weight floor impact sounds. Through the evaluation of dynamic stiffness and single-number quantities, a high correlation was observed at 125 Hz and 500 Hz for heavy-weight floor impact sounds and across all octave bands for light-weight floor impact sounds. The analysis of dynamic stiffness and single number quantity revealed a high correlation in both heavy weight and light weight floor impact sound. Lower dynamic stiffness was confirmed to be advantageous for reducing floor impact noise.

Reduction in Floor Impact Sound and Vibration Acceleration Levels of Ceiling Structure by Installing Anti-vibration Hangers

Reduction in Floor Impact Sound and Vibration Acceleration Levels of Ceiling Structure by Installing Anti-vibration Hangers

Current Performance of Floor Impact Sound Insulation in Wooden Apartment Buildings in Hokkaido

In Hokkaido, Japan, technological developments have been introduced to improve the floor impact sound insulation performance in wooden apartment buildings. However, such technological developments are not widely used, especially in rental properties. To effectively disseminate the required technology, it is vital to report examples of implementation. Therefore, we measured the performance of five types of wooden apartment buildings with high sound insulation performance and analyzed the results. The main results are listed below. (1) A relatively high performance was obtained by installing a floating floor and an independent ceiling. (2) For heavy weight floor impact sound insulation of a car tire source, a floating floor with a surface density of 60 kg/m2 or higher could achieve a performance of Li,Fmax,r,H(1)-60 or higher. However, in the case of a rubber ball source, vibration radiation noise from the wall surface of the lower floor is large, so it is necessary to consider vibration countermeasures. (3) For light weight floor impact sound insulation, sufficient performance cannot be obtained even with a floating floor. Therefore, carpet or wooden soundproof flooring should be used. (4) The light weight floor impact sound pressure level is high when the floor area of the sound receiving room is small.

Round-robin tests of the different types of sensors for floor impact sounds and vibrations

Recently, floor impact noise monitoring system was introduced for residents to control making noises spontaneously using sound and vibration sensors. The present study aims to investigate the performance and characteristics of various current using sound and vibration sensors which can be eventually compatible with the floor impact noise monitoring system. For measurements of sound sensors, 7 sound microphones were used including 2 condenser types, 4 dynamic types, and 1 electro condenser type. Also, 6 vibration meters were used including 2 MEMS types, 2 Piezo types, and 2 spring types. Sound levels were measured in a semi-anechoic chamber using white noise in the frequency range from 63 Hz to 12.5 kHz. Vibrations were measured using high density wooden panel with an impact ball in the frequency range from 16 Hz to 4 KHz. Round-robin tests were done to confirm the exact performances of all the sensors under same condition. As a result, it was found that dynamic type microphones show the most similar response characterization in comparison with the reference condenser microphone especially in the air-borne sound frequency range from 250 Hz to 2 KHz. Also, it was found that spring type vibration meters show the most appropriate characterization at 63 Hz, most critical structure-borne sound frequency. Thus, the results drawn from the round-robin tests could be used for floor impact noise monitoring systems with the benefit of both economy and performance.

A Study on Floor Impact Sound Insulation Performance of Cross-Laminated Timber (CLT): Focused on Joint Types, Species and Thicknesses

A Study on Floor Impact Sound Insulation Performance of Cross-Laminated Timber (CLT): Focused on Joint Types, Species and Thicknesses

Finite element analysis of bending waves in Mindlin plates with Perfectly Matched Layers

It is important to determine the boundary conditions of walls and floors precisely when simulating the building acoustics. For a certain room, the extension of the spans can be considered as infinite edges. The Perfect Matched Layer(PML) is an artificial absorbing domain for the wave propagations and is widely used in finite element analysis to simulate the acoustical free field conditions right now. In this paper, an effective PML technique for the plate structure will be presented. The PML formulation will be derived based on the Mindlin plate theory and the implementation method will be introduced. This technique will be validated through the numerical experiments. The accuracy and limits of the presented technique will be discussed based on the numerical results compared with the analytical results. The results show that the presented PML technique is effective and accurate to simulate the plate as an infinite large plate. It is expected to implement the technique in the further research of the structure borne sound, such as floor impact sounds.

Spatial distribution of heavy-weight floor impact sounds according to the household location in a box-frame concrete building

In this study, factors influencing the heavy-weight floor impact sounds were analyzed in situ while considering 59 households in a residential building with identical plans and floor structures. A formula to calculate the contribution of the Li,Fmax of each frequency band to the LiA,Fmax was suggested and the main frequency range was determined as 95% of the LiA,Fmax. Further, a hierarchical cluster analysis was conducted on the Li,Fmax, derived for the main frequency range for a rubber ball and a tire each. As a result, the similarity between heavy-weight floor impact sounds in households located on the same floor was found to be higher than that between sounds in households located on different floors. This difference may be attributed to the fact that the households on the same floor share the same floor slab.

프리캐스트 콘크리트 모듈러 병동 목업의 음향성능 평가

The hospital environment affects patient satisfaction. Excessive noise in the ward hinders patients’ sleep and rest. Moreover, it affects communication between medical staff, patients, and visitors. Precast concrete modular structures have the advantage of shortening the construction period compared to reinforced concrete buildings. Owing to this advantage, modular hospitals are expected to be useful for production and supply in emergency situations such as pandemics. This study aimed to measure the floor impact and airborne transmission sounds of a precast concrete modular ward to evaluate whether they meet noise standards. Light-weight impact sounds (L’SUBn,w/SUB) were measured at 52 dB and 54 dB and heavy-weight impact sounds (L’SUBiA,Fmax/SUB) at 62.8 dB and 63.6 dB in two tested wards. The sound reduction index (R’SUBw/SUB) between the two rooms was 51 dB. The insulation performances of light-weight impact sound and airborne sound were found to satisfy most of the minimum standards set by countries of the European.

The Improvement on Floor Impact Sound Insulation by Interior Decoration

我國建築法規防音條文並未規定既有住宅分戶樓板之隔音構造及基準，若產生樓板衝擊音之問題，除協調上層住戶以樓板表面材作為衝擊音改善對策外，僅能以自有權屬空間進行隔音設計，或藉由室內裝修設計方式獲得較佳之居住音環境品質。因此，本研究選定國內鋼筋混凝土造住宅，進行室內天花板搭配牆體裝修施工，參照CNS15160-7量測標準進行樓板衝擊音隔音現場量測，並依CNS8465-2進行量測結果之單一數值評定，瞭解衝擊音頻率特性與裝修構造之隔音性能。研究結果顯示，室內天花板及牆體裝修構造後，空間衝擊聲壓位準在頻率100～1000Hz之數值隨迴響時間下降而減少，有利於衝擊音之改善。而受測空間經天花板裝修後，可阻隔約7～8分貝之樓板衝擊音隔音，若增加牆體裝修構造，衝擊音隔音可提升至13～15分貝，降低衝擊源能量透過樓板或側牆等結構傳音，有效解決既有住宅衝擊音干擾之問題。In this research, we discussed the methods to improve the impact sound insulation of floor slabs of the existing residents. The reinforced concrete house was our object, we decorated the ceiling and wall in our object and followed the standard of CNS 15160-7 to measure the field of floor impact sound and then calculated the single number by CNS 8465- 2. In this study, we understood the frequency property of impact sound and the insulation performance of decorating structures. The result shows decorating the ceiling and wall was to affect the values of the reverberation time of receiving room and reduced the impact sound pressure level of 100~1000 Hz. It had the performance that floor impact sound was deceased 7~8 dB by decorating the ceiling. To add the wall structure design that could provide 13~15 dB in the insulation performance of floor impact sound. In this study we found that decorating ceilings and walls could solve the problem of floor impact noise in existing residences and improve the transmission of the impact source energy with the building floor or structure.

Acoustic Retrofit Approach of an Apartment Living Room Using Multi-Perforated Gypsum Boards in Terms of Heavy-Weight Impact Sounds

In this study, the effects of multi-perforated gypsum boards on floor impact noises were investigated in a box-type test building and an actual apartment building. In a box-type test building with 150 mm thick slab, various design factors such as hole pattern, hole size, opening ratio, backing, or finishing materials were considered. Heavy-weight impact sources of bang machine and rubber ball were employed. The test procedure followed KS F 2810-2, and then, a single number rating was derived in accordance with KS F 2863-2. As a result, reduction of heavy-weight impact noise by applying multi-perforated gypsum boards as a ceiling material was expected maximumly up to 3 dB for bang machine and 5 dB for rubber ball. Regarding the reduction of floor impact sounds at frequencies above 125 Hz, the installed area of the employed multi-perforated gypsum board was shown as the most dominant factor. Then, an in situ investigation using standard impact sources and five children was carried out in an actual living space of an actual apartment dwelling unit. Comparing before and after installation of multi-perforated gypsum board, 1–2 dB of heavy-weight impact noises was reduced. In addition, subjective impressions of the reduced impact noise were discussed based on the field questionnaire survey using actual children’s running situations.

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.

실제 어린이 뜀 분석을 통한 신중량 충격모델 개발

The quietness of a living space greatly affects the quality of life of its residents. To maintain the quietness of an indoor space, a solution is required for the floor impact sounds that have over the years generated several civil complaints to the National Noise Information System. Accurate measurement and evaluation of the floor structure are important factors for solving the floor impact sounds. To reproduce the sound effect of children running on the floors accurately, a new impact source is designed that complements the current standard impact sources. Prior to the designing, the important factors were investigated via a questionnaire answered by experts. The experts

Background Noise, Noise Sensitivity, and Attitudes towards Neighbours, and a Subjective Experiment Using a Rubber Ball Impact Sound.

When children run and jump or adults walk indoors, the impact sounds conveyed to neighbouring households have relatively high energy in low-frequency bands. The experience of and response to low-frequency floor impact sounds can differ depending on factors such as the duration of exposure, the listener’s noise sensitivity, and the level of background noise in housing complexes. In order to study responses to actual floor impact sounds, it is necessary to investigate how the response is affected by changes in the background noise and differences in the response when focusing on other tasks. In this study, the author presented subjects with a rubber ball impact sound recorded from different apartment buildings and housings and investigated the subjects’ responses to varying levels of background noise and when they were assigned tasks to change their level of attention on the presented sound. The subjects’ noise sensitivity and response to their neighbours were also compared. The results of the subjective experiment showed differences in the subjective responses depending on the level of background noise, and high intensity rubber ball impact sounds were associated with larger subjective responses. In addition, when subjects were performing a task like browsing the internet, they attended less to the rubber ball impact sound, showing a less sensitive response to the same intensity of impact sound. The responses of the group with high noise sensitivity showed an even steeper response curve with the same change in impact sound intensity. The group with less positive opinions of their neighbours showed larger changes in their subjective response, resulting in the expression of stronger opinions even to the same change in loudness of the impact sound. It was found that subjective responses were different when subjects were performing activities of daily living, such as reading or watching TV in the evening, and when they were focused on floor impact sounds in the middle of the night.

중량충격음 레벨의 주관적 인지 변화에 대한 연구: 동일한 단일수치 평가량을 갖는 충격음을 대상으로

중량충격음 레벨의 주관적 인지 변화에 대한 연구: 동일한 단일수치 평가량을 갖는 충격음을 대상으로

공동주택 뜬바닥 구조층 구성에 따른 바닥충격음 차단성능 실험적 연구

공동주택 뜬바닥 구조층 구성에 따른 바닥충격음 차단성능 실험적 연구

유한요소해석을 이용한 중량충격원 종류 및 평가지표 별 바닥충격음 예측 정확도 검증

In this study, we determined the reliability of the finite element method in predicting heavy-weight floor impact sounds after comparing the predicted and measured frequency response functions of vibration and acoustic sounds in full-scale houses. The heavy-weight impact source included a bang machine and rubber ball. For both vibration and acoustic modes, the predicted frequency response functions showed a similar amplitude as the measured ones. However, there was a small difference in their peak frequencies owing to the non-linear characteristics of concrete. The heavy-weight impact sound from the bang machine was predicted to have a 1 dB deviation when compared with the experimental results and a 2.1 dB deviation in total sound pressure level. The deviation between the experimental and simulation results for the rubber ball was 1 dB for impact sound and 0.5 dB in total sound pressure level. The maximum deviation at each frequency was 5 dB and 4 dB for the bang machine and rubber ball, respectively. Overall, the results indicate that the numerical analysis is useful for developing optimized structures to control heavy-weight floor impact sound with different impact sources and evaluation indices.

공동주택 바닥 공사 공정별 바닥충격음 특성 분석

공동주택 바닥 공사 공정별 바닥충격음 특성 분석

Influence of Perforated Ceiling on Floor Impact Sound Insulation in Reinforced Concrete Buildings

In this study, the influence of a perforated ceiling on the floor impact sound was investigated. The floor impact sound measurements were conducted both with and without suspended ceiling including the perforated and nonperforated panel, using heavy and light weight impact sources in a reinforced concrete test building. The results indicated that the perforated ceiling with and without absorption sheet greatly reduced the resonance of floor impact sound by the non-perforated ceiling. However, the perforated ceiling without an absorption sheet did not improve the single number quantity (SNQ, rubber ball: L′iA,Fmax,V.T and tapping machine: L′n,w) for the floor impact sound insulation. The perforated ceiling with attached absorption sheet produced SNQs of 2 dB lower and higher than that produced by the non-perforated ceiling for heavy and light weight impact sources, respectively. It was also found that the improvement in the floor impact sound insulation after the installation of the perforated ceiling was related to the mass-spring-mass system, rather than the absorption area of the receiving room.

노후 공동주택 바닥구성층 수선에 따른 충격음 차단성능 개선

노후 공동주택 바닥구성층 수선에 따른 충격음 차단성능 개선

Evaluation of the Floor Impact Sound Insulation Performance of a Voided Slab System Applied to a High-Rise Commercial Residential-Complex Building

Multi-unit dwellings, such as apartment housing, town houses, and flats, are some of the most common housing types in Korea, as well as in other countries. Such multi-unit dwellings are considered an effective means to overcome the housing problems of high-density population in urban areas, owing to their high efficiency of land utilisation. However, interlayer noise complaints, such as footsteps or dragging items in apartment housing, are an inevitable problem in apartment dwelling conditions, because each household in an apartment shares walls and ceilings with other households. This paper presents the results acquired from the field test of the floor impact sound insulation performance of a voided slab system as applied to a commercial residential-complex building in South Korea. The results have shown that adopting the voided slab system for a commercial residential-complex building increased floor impact sound insulation performance. The test results show that the sound insulation performance of the voided slab system applied in the building for lightweight and heavyweight floor impact sound reached (47 and 41) dB, respectively. Based on the results of the field tests, it is expected that the application of the voided slab systems to the slabs of the apartment dwellings would be effective, and offer outstanding sound insulation performance. Moreover, it is expected that the floor impact sound insulation performance would be further improved, if the floor finishing materials, such as carpet or other types of flooring material, would first be installed onto the floor.