Inter-floor Noise Research Articles

A Case Study of Frequency Analysis of the Contribution of a Single Number Quantity to the Introduction of Rubber Ball Impact Sound and Changes in Assessment Methods

This study analyzed the effects of changes in the inter-floor noise assessment system in multi-family housing in Korea on heavy-weight impact sound performance assessment. By comparing the existing pre-approval system with the newly introduced post-verification system, we focused on the effects of the evaluation criteria, impact sources, and frequency band considerations on the single numerical evaluation quantities (L’i,Fmax,AW and L’iA,Fmax) and contribution rates by frequency band. For the analysis, impact sounds were measured using a bang machine used in the existing pre-approval system and a rubber ball used in the post-verification system, and the performance of the floor structure was evaluated in the 1/1 and 1/3 octave bands. As a result, the pre-approval system showed a high contribution rate mainly in the 63 Hz band, but the post-verification system expanded the contribution rate to the mid-low frequency band of 63–160 Hz. In particular, the evaluation method using the A-weighted maximum floor impact sound level (L’iA,Fmax) of the post-verification system was found to reflect the performance in the mid- and high-frequency band of 125–250 Hz more effectively. The post-verification system enables a more accurate evaluation of the performance of high-frequency bands that were overlooked in the existing system, thereby enabling a realistic response to the mitigation of inter-floor noise. Accordingly, construction companies must meet stricter performance standards in floor structure design and resilient materials development, in accordance with the new regulations. For example, designs utilizing sound-absorbing ceiling structures and high-performance resilient materials are expected to be effective in reducing heavy-impact noise. This study provides important basic data for tracking the performance of floor structures according to changes in the system, and selecting key frequency bands for reducing heavy-impact noise. In addition, it emphasizes the need to continuously monitor the performance of multi-family housing constructed under the new system and to derive effective design strategies for solving inter-floor noise problems. In the future, it will be necessary to expand the usability of the results of this study through additional studies targeting more diverse floor plans and floor structures.

Comparing self-generated noise reduction efforts and tolerance of neighbours’ noise in multi-residential buildings

Interfloor noise is a significant issue in multi-unit residential buildings and affects the quality of life of residents. Understanding the dynamics of noise generation and perception among residents is crucial for developing effective noise-management strategies. This study aims to investigate the similarities and differences in attitudes towards noise disturbance from the perspectives of both noise creators and listeners in multi-unit residential buildings. Additionally, it sought to understand the relationship between residents' efforts to minimise noise in their homes and their tolerance levels to noise from adjacent apartments. An online questionnaire survey on interfloor noise was conducted among 1989 South Koreans aged 20–89 years. The survey assessed noise reduction efforts, noise tolerance levels, and attitudes towards different types of noise during the day and night. Most respondents reported above-average noise reduction efforts, whereas noise tolerance was evenly distributed. A weak negative correlation was found between the overall effort and tolerance. However, the nighttime noise reduction effort was positively correlated with daytime noise tolerance. Despite being a primary complaint source, floor impact noise was considered less significant in residents' reduction efforts. Age-related differences were observed, with older adults showing increased effort and uniform tolerance, and younger adults focusing more on daytime noise reduction. This study underscores the need for a multifaceted approach to noise management in multi-unit residential buildings. These findings suggest that uniform strategies may be inadequate owing to the interplay between age, noise generation, and tolerance. Effective noise control may require resident education on floor impact noise, age-specific noise policies, and targeted noise reduction solutions based on the noise type and source. This approach can contribute to creating a more harmonious living environment for residents of all ages.

Heavy-weight impact sound insulation characteristics related with vibrational properties of Korean domestic CLT slabs with different species and joint types

Korea has the world's most strict inter-floor noise regulations. In order to build an apartment house with more than 30 units, it must meet the minimum requirement of impact sound level, single number quantities of 49 dB. These regulations make it hard to expand residential tall wood building in Korea. For making quality satisfied CLT floors, as the preliminary investigations, the effects of wood species and CLT panel joints on the vibration and sound insulation performance of CLT were analyzed. The natural frequency range of the CLT slabs is from 20 Hz to 22 Hz. There were no significant differences depending on wood species and CLT panel joint type. As the stiffness of the slabs increased, the floor impact sound insulation performance also improved. The deflection model for CLT slabs was developed and validated with the actual deflection derived by acceleration spectrum. The measured value was 62 ~ 87% of the predicted value.

범죄피해자 심리지원의 실태 및 개선방안

Recently, in April 2024, there was a shocking report about a teenager being stabbed by a neighbor in his 50s due to inter-floor noise conflict in an apartment complex, resulting in serious injuries and traumatic distress. The psychological shock experienced by victims of violent crimes like this is beyond imagination, necessitating a response. While the Crime Victim Protection Act is being enforced, providing financial and psychological support, it's time for proactive measures from the perspective of victims' human rights. Historically, the judicial system in Korea has prioritized the rights of suspects and defendants, often neglecting the needs of the victims. The purpose of this paper is to examine the current state of support for crime victims, particularly in terms of psychological support, and explore the problems of the crime victim psychological support system and seek improvement measures. Based on an analysis of the current state of the crime victim support system, previous research, and factual diagnosis, discussions were conducted on the problems and improvement measures of psychological support for crime victims. As a result, the following conclusions were reached: Firstly, there is a need for legal policy improvements, including shifting perceptions, focusing on psychological support, and proposing legislative amendments. Secondly, institutional improvement measures, such as enhancing professionalism, strengthening the role of centers, providing support from the victim's perspective, and preparing for remote counseling, are necessary. Thirdly, the continued development of the police's psychological system is essential.

Numerical Investigation on the Natural Frequency of RC Slab Reinforced with Cambered Steel Beam for Reducing Heavy-Weight Impact Noise

In an apartment building, inter-floor noise occurs due to the residents' movements. The floor impact noises are divided into light and heavy-weight impact sounds depending on the impact source. This study proposed cambered steel beam reinforcement technology installed under floor slab to reduce heavy-weight impact noise. The beam for stiffness reinforcement is supported by both side of the walls in the ceiling structure, and it reduces inter-floor noise by applying upward force to the bottom surface of the slab and controlling the slab vibration characteristics. In order to verify the effectiveness of the proposed technology and investigate the natural frequency of the floor, finite element analysis model was developed for the 84m2 type apartment plan with bearing wall structure. From the eigenvalue analysis, it is known that the first natural frequency increased by 0.37~12.67% depending on the cross-section size of the cambered steel beam. Based on the first natural frequency, as a result of evaluating the vibration standards of residential buildings presented in DIN 4150-2, the vibration characteristics of the slab were improved by reducing the vibration value KB by up to 75.20%. Therefore, this study indicated that in an apartment building reinforced with cambered steel beams, inter-floor noise caused by heavy-weight impact sound was reduced.

Source Type Classification and Localization of Inter-Floor Noise with a Single Sensor and Knowledge Transfer between Reinforced Concrete Buildings

A convolutional neural network (CNN)-based inter-floor noise source type classifier and locator with input from a single microphone was proposed in [Appl. Sci. 9, 3735 (2019)] and validated in a campus building experiment. In this study, the following extensions are presented: (1) data collections of nearly 4700 inter-floor noise events that contain the same noise types as those in the previous work at source positions on the floors above/below in two actual apartment buildings with spatial diversity, (2) the CNN-based method for source type classification and localization of inter-floor noise samples in apartment buildings, (3) the limitations of the method as verified through several tasks considering actual application scenarios, and (4) source type and localization knowledge transfer between the two apartment buildings. These results reveal the generalizability of the CNN-based method to inter-floor noise classification and the feasibility of classification knowledge transfer between residential buildings. The use of a short and early part of event signal is shown as an important factor for localization knowledge transfer.

Inter-floor noise classification using convolutional neural network.

In apartment houses, noise between floors can disturb pleasant living environments and cause disputes between neighbors. As a means of resolving disputes caused by inter-floor noise, noises are recorded for 24 hours in a household to verify whether the inter-floor noise exceeded the legal standards. If the noise exceeds the legal standards, the recorded sound is listened to, and it is checked whether the noise comes from neighboring households. When done manually, this process requires time and is costly, and there is a problem of whether the listener’s judgments of the sound source are consistent. This study aims to classify inter-floor noise according to noise sources by using a convolutional neural network model. A total of 1,515 sound sources of data recorded for 24 h from three households were annotated, and 40 4s audio clips of six noise sources, including “Footsteps,” “Dragging furniture,” “Hammering,” “Instant impact (dropping a heavy item),” “Vacuum cleaner,” and “Public announcement system” were identified. Moreover, datasets of 16 classes using ESC50’s urban sound category audio were used to distinguish the inter-floor noise heard indoors from the external noise. Although DenseNet, ResNet, Inception, and EfficientNet are models that use images as their domains, they showed an accuracy of 91.43–95.27% when classifying the inter-floor noise dataset. Among the reviewed models, ResNet showed an accuracy of 95.27±2.30% as well as a highest performance level in the F1 score, precision, and recall metrics. Additionally, ResNet showed the shortest inference time. This paper concludes by suggesting that the present findings can be extended in future research for monitoring acoustic elements of indoor soundscape.

기존 표준 충격원의 개선 필요성 및 신 연발성 충격원 개발 방향에 대한 전문가 대상 설문조사

Apartments are a suitable type of housing for a densely populated nation like Korea. Most of the complaints in apartment buildings are about the noise between floors. While children running are the main cause of inter-floor noise and have a moving point of continuity, the standardized impact source currently in use has a standing impact point. Before developing a new impact sound source model for simulations of children running, a survey was conducted to obtain expert opinions. A total of 50 respondents were surveyed in person, and their responses were analyzed. The experts agreed on the need for new continuous impact source models. They also preferred to study the influence of children running, continuity, and the movement of the impact point. The A-weighted sound pressure level was assessed to be the best-suited evaluation index.

Preparation and properties of ethylene-vinyl acetate copolymer-based blend foams

In this study, ethylene-vinyl acetate (EVA) copolymer-based blend foams with polyolefin elastomers (POEs), low-density polyethylene, or styrenic thermoplastic elastomers were prepared as a potential resilient material for reducing inter-floor noise. Various properties of EVA blend foams were measured in order to reveal the effects of EVA content and types of pair polymers consisting of EVA blend foams on dynamic stiffness, which is one of the key factors of resilient materials, in relation to hardness, specific gravity, and resilience. These properties had not been introduced by the construction industry until now. When the EVA/POE ratio was 20/80 and the foaming ratio was 210%, dynamic stiffness presented the lowest value at 5.97 MN m− 3. However, when the resilience was <20%, dynamic stiffness was as high as 37.66 MN m− 3 at an expansion ratio of 210% even when the specific gravity was low.

A learning-based classification of indoor noise type/position in an apartment building

This study presents a learning-based method as an indoor noise source type/position classification technique closely related to the interfloor noise problem causing serious conflict between South Korean neighbors. For this study, an indoor noise dataset recorded by a single mobile phone was collected on three floors of an apartment building. Using a convolutional neural networks based classifier, the data containing five source type labels and four position labels is trained and evaluated. In addition, unlabeled data that is not used in the model development is tested for robustness evaluation of our classification system.

Classification of Inter-Floor Noise Type/Position Via Convolutional Neural Network-Based Supervised Learning

Inter-floor noise, i.e., noise transmitted from one floor to another floor through walls or ceilings in an apartment building or an office of a multi-layered structure, causes serious social problems in South Korea. Notably, inaccurate identification of the noise type and position by human hearing intensifies the conflicts between residents of apartment buildings. In this study, we propose a robust approach using deep convolutional neural networks (CNNs) to learn and identify the type and position of inter-floor noise. Using a single mobile device, we collected nearly 2000 inter-floor noise events that contain 5 types of inter-floor noises generated at 9 different positions on three floors in a Seoul National University campus building. Based on pre-trained CNN models designed and evaluated separately for type and position classification, we achieved type and position classification accuracy of 99.5% and 95.3%, respectively in validation datasets. In addition, the robustness of noise type classification with the model was checked against a new test dataset. This new dataset was generated in the building and contains 2 types of inter-floor noises at 10 new positions. The approximate positions of inter-floor noises in the new dataset with respect to the learned positions are presented.

Practical Inter-Floor Noise Sensing System with Localization and Classification.

Inter-floor noise is a severe social problem which causes illegal arson, violence, and even murder. In this paper, an inter-floor noise sensing system is proposed to detect and record information related to inter-floor noise in an apartment building. The proposed system measured the noise level and estimated the direction of the noise source along with the type of noise. The noise level measurement is based on the sound pressure level (SPL) measurement, which is a logarithmic measure of the effective pressure of a sound relative to a reference sound pressure. Noise source localization was performed using the estimated time difference of arrival (TDOA) from the microphone array. For the classification of noise types, the Mel frequency cepstral coefficients (MFCC) and zero-crossing rate (ZCR) were extracted from a noise signal, and the k-nearest neighbor algorithm was used to classify the type of noise. In addition, we developed a noise monitoring hardware to evaluate our methods in the actual environment. The experimental results demonstrated that the proposed system had a reliable accuracy for each functional unit. The results showed that the error of the noise level was approximately ±1.5 dB(A), the error of the direction estimation was approximately ±10°, and the accuracy of the classification for the noise type was more than 75%. These output data from the proposed system are expected to be used as important reference data for any dispute cases due to inter-floor noise.

Classification of inter-floor noise type/position via supervised learning

This work presents noise type/position classification of various inter-floor noises generated in a building which is a serious conflict issue in apartment complexes. For this study, a collection of inter-floor noise dataset is recorded with a single microphone. Noise types/positions are selected based on a report by the Floor management Center under Korea Environmental Corporation. Using a convolutional neural networks based classifier, the inter-floor noise signals converted to log-scaled Mel-spectrograms are classified into noise types or positions. Also, our model is evaluated on a standard environmental sound dataset ESC-50 to show extensibility on environmental sound classification.

Downstairs resident classification characteristics for upstairs walking vibration noise in an apartment building under virtual reality environment

Psychoacoustic experiments were performed to investigate head-related transfer function (HRTF) and head-mounted display (HMD) effects, to develop a new virtual-reality (VR)-based noise assessment methodology and classification method for heavy-weight impact sounds in an apartment indoor environment. Sound pressure levels and frequency characteristics before and after HRTF application were examined to reproduce the “upstairs condition” (overhead movement), for a heavy-weight impact source recorded in an apartment living room. Floor impact noise was assessed using the HMD by modeling a typical living room. For four environments (NONE, HRTF, HMD, and HRTF + HMD), subjective responses (annoyance, allowance limit, semantic expression) were examined for 38–62-dB maximum sound pressure levels with an A-weighted frequency response and fast time constant. Directional information through the HRTF significantly increased annoyance and decreased the allowance limit, and HMD visual information partially (1.2 times) affected the allowance limit in a high inter-floor noise environment owing to increased visual involvement (56 dBA). The semantic expression assessment revealed comprehensive inter-floor noise responses of dissatisfaction, irregularity, and discontinuity, and confirmed greater annoyance due to walking vibration noise in an environment with directional information, because of increased perception of heavy-impact sound-induced discomfort. Regarding annoyance- and allowance-limit-based classification, the satisfaction standards for low-noise environments were assessed as 6–7 dB lower than those of previous studies when both HRTF and HMD were applied, confirming that test subjects respond to noise more sensitively in a virtual environment where audiovisual information is provided. Therefore, a new indoor noise assessment methodology for environmental factors is proposed herein.

Elastic Metamaterial Insulator for Broadband Low-Frequency Flexural Vibration Shielding

Vibration shielding is a core concept in applications including precision manufacturing, vehicle design, and interfloor noise reduction in architecture. Blocking broad ranges of extremely low frequencies remains a challenging, unresolved problem. The authors present an elastic metamaterial based on the dual ideas of $r\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}n$ $s\phantom{\rule{0}{0ex}}o\phantom{\rule{0}{0ex}}f\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}g$ and $s\phantom{\rule{0}{0ex}}h\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}a\phantom{\rule{0}{0ex}}r$ $s\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}f\phantom{\rule{0}{0ex}}f\phantom{\rule{0}{0ex}}e\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}g$, to shield against flexural waves from 235 to 4520 Hz, covering nearly the entire range of conventional frequencies. These small, lightweight, mass-beam-plate structures could provide many solutions in acoustic engineering.

층간소음의 제 문제에 관한 법적 검토

소음은 원하지 않는 소리 또는 듣는 이의 활동에 영향을 미치는 것으로 그 악영향은 불특정 다수인에게 미치는 공해이며 환경에 대한 적극적 침해에 속한다. 이러한 소음은 인체 및 심리에 부정적인 영향을 미쳐 인체의 전반적인 나쁜 감수성을 증가시킨다. 즉 소음은 우리 일상생활의 결과이면서 청력손상, 수면장애, 불쾌감 등 생활환경을 악화시키는 요소이며 이에 대한 반응은 매우 주관적이고 가시적인 피해가 축적되지 않는 특징을 지닌다. 특히 층간소음은 건물의 위층 아래층 사이뿐만 아니라 옆집 사이에서 전파되는 소음에 속하는 것으로서 아이들이 뛰거나 벽에 몸을 부딪치는 등 벽이나 바닥에 직접 충격을 가해 생기는 소음과 텔레비전, 오디오, 피아노 등 악기에서 발생하여 공기를 타고 전파되는 소음을 말한다. 그러나 층간소음 피해자인 공포와 불안 등 노이로제, 정서장애, 우울증, 불면증 등에 대하여 가해자의 상습적이며 고의적인 행동에 대하여 엄격한 법적 제재를 가하는 것은 사후약방문에 불과하다. 특히 층간소음과 관련하여 ‘사람의 신체의 안전 및 건강’과 ‘사생활의 평온과 안전’이라는 법익은 개인과 사회의 포기되어질 수 없는 권리와 이익이므로, 층간소음으로 인한 형법상 제재는 다른 규범에 비해 중요성과 절박성이 큰 규범이므로 이에 대한 신중한 검토가 요구되며, 새롭게 부각되고 있는 범죄에 관한 대응을 위해서도 적극적인 형법상의 개선방안이 고려된다. 현대사회의 복잡성을 고려할 때 위험사회에서 형법의 상징화와 기능화는 어느 정도 필연적일지라도, 이성적인 형법의 산물인 죄형법정주의와 책임원칙, 비례원칙, 보충성원칙과 같은 근대 형법원칙들의 본질을 훼손시켜서는 아니 될 것이다. 무엇보다도 층간소음 문제로 인한 2차 범죄발생을 효과적으로 예방할 수 있도록 하는 것이 중요하다. 최근 갑작스럽게 발생하는 끔찍한 대형사고를 경험하면서 현대 위험사회의 도래에 더욱 큰 대형사고를 미연에 방지하는 범죄예방 차원에서 엄격한 법적 제재가 이루어져야 함은 물론이다. 그러기 위해서는 현실에 부합되는 법률제도의 정비와 정책의 집행 또한 필요하다. 아울러 주민들의 공동체의식을 강화하고 상호간의 생활배려의 상린관계의 상생협력정신은 이 시대의 필연적인 요구사항이라고 할 수 있다. 결국 공동주택의 층간소음 해결을 위해서는 실효성있는 법적 근거 마련 및 국토교통부의 실내소음측정과 층간소음 기술적 표준의 제시 및 환경부의 적극적인 정책추진이 필요한 상황이다. 현재 환경부에서 추진 중인 층간소음의 상황별 대응방안의 홍보 및 교육, 층간소음 상담제도의 확대, 분쟁조정 기준의 내실화 및 분쟁 발생시 적극적인 대응과 함께 기술적 해결 방안 마련을 위한 지속적인 데이터 축적과 분석은 매우 중요하다 할 수 있다. 무엇보다도 층간소음에 관하여는 정부, 업계, 학계 전문가들이 공동으로 층간소음 문제해결을 위한 협력체계를 구축하여 층간소음 원인규명을 위한 정밀측정방법 및 분쟁 발생시 조정을 위한 적극적인 해결 방법의 개선 및 연구가 지속되어야함은 물론이다. 그리고 공동주택에서의 이웃 상호간의 상린관계에서의 이해와 상생협력적인 아름다운 주민생활의 형성은 매우 중요하다 할 수 있다.

Study on Noise Characteristics of Facility Equipment and Subjective Responses

For a house to maintain the standards of a quiet residential environment, it is necessary to reduce not only inter-floor noise delivered from neighboring houses but internal noise sources as well. Currently, noise measures on facility and equipment have been established in apartment houses in South Korea. This study aimed to provide foundational data needed to provide institutional standards on facility noise in apartments. Thus, this study analyzed noise level and acoustical parameters (loudness, sharpness, and roughness) with regard to noises from hoods and boilers in kitchens. This study also studied an annoyance rating, which was a subjective response to the noise, using 36 subjects. It also quantified a subjective response by calculating a %HA (percentage of highly annoyed) according to the maximum noise level from a boiler and kitchen hood, and a mean value of annoyance. No significant difference between the two rating scales was found.

공동주택 거주자의 층간소음 갈등 경험에 따른 사회적 해결방안

This study aims to develop a solution to inter-floor noise complaints by exploring cases of noise complaints between floors and by identifying the demands and needs of the residents. For this purpose, a survey was conducted targeting residents who were sorted into groups depending on their experiences with inter-floor noise. This survey was carried out from June 11, 2014 to June 16, 2014. A total of 100 copies of the questionnaire was distributed to the residents, of which 98 were completed and collected. Data were statistically processed in accordance with SPSS WIN 18.0. The results showed that the leading causes of inter-floor noise complaints were residents' differences in schedules and their inconsideration in behavior. Thus, the solution to this issue is three-fold: first, to take social measures in order to improve communication and understanding between residents so they can be mindful of their noise levels; second, to reinforce noise control regulation; and third, to improve noise reduction design within the building architecture.

Legal Consideration For Resolution Of Efficient Over Inter-Floor Noise Disputes In An Multi-Family House - Based on the review of dispute resolution means -

Legal Consideration For Resolution Of Efficient Over Inter-Floor Noise Disputes In An Multi-Family House - Based on the review of dispute resolution means -