Structure-borne sound in buildings: Advances in measurement and prediction methods

2020 ◽  
Vol 68 (1) ◽  
pp. 1-20 ◽  
Author(s):  
Barry Marshall Gibbs ◽  
Michel Villot

This article coincides with recent publications of international standards, which provide methods of predicting the performance of both heavyweight and lightweight buildings in terms of airborne sound insulation and impact sound isolation, from the performance of individual elements such as walls and floors. The performances of the elements are characterized by the sound reduction index and the impact sound pressure level. To predict the sound pressure level due to vibrating sources (i.e., mechanical installations, water services and other appliances), source data are required in a form appropriate as input for prediction models similar to the above, i.e., as equivalent single quantities and frequency band-averaged values. Three quantities are required for estimating the structure-borne power for a wide range of installation conditions: activity (the free velocity or the blocked force of the operating source), source mobility (or the inverse, impedance) and receiver mobility (or impedance) of the connected building element. Methods are described for obtaining these source quantities, including by using laboratory reception plates. The article concludes with a proposed database, based on laboratory measurements and simple mobility calculations, which provides a practical approach to predicting structureborne sound in buildings.

2020 ◽  
Vol 18 (2) ◽  
pp. 1451-1463
Author(s):  
Witold Mikulski

Abstract Purpose The purpose of the research is to work out a method for determining the sound insulation of acoustic enclosures for industrial sources emitting noise in the frequency range of 10–40 kHz and apply the method to measure the sound insulation of acoustic enclosures build of different materials. Methods The method is developed by appropriate adaptation of techniques applicable currently for sound frequencies of up to 10 kHz. The sound insulation of example enclosures is determined with the use of this newly developed method. Results The research results indicate that enclosures (made of polycarbonate, plexiglass, sheet aluminium, sheet steel, plywood, and composite materials) enable reducing the sound pressure level in the environment for the frequency of 10 kHz by 19–25 dB with the reduction increasing to 40–48 dB for the frequency of 40 Hz. The sound insulation of acoustic enclosures with a sound-absorbing material inside reaches about 38 dB for the frequency of 10 kHz and about 63 dB for the frequency of 40 kHz. Conclusion Some pieces of equipment installed in the work environment are sources of noise emitted in the 10–40 kHz frequency range with the intensity which can be high enough to be harmful to humans. The most effective technical reduction of the associated risks are acoustic enclosures for such noise sources. The sound pressure level reduction obtained after provision of an enclosure depends on its design (shape, size, material, and thickness of walls) and the noise source frequency spectrum. Realistically available noise reduction values may exceed 60 dB.


2012 ◽  
Vol 30 (4) ◽  
pp. 349-359 ◽  
Author(s):  
Edith Van Dyck ◽  
Dirk Moelants ◽  
Michiel Demey ◽  
Alexander Deweppe ◽  
Pieter Coussement ◽  
...  

The present study aims to gain better insight into the connection between music and dance by examining the dynamic effects of the bass drum on a dancing audience in a club-like environment. One hundred adult participants moved freely in groups of five to a musical sequence that comprised six songs. Each song consisted of one section that was repeated three times, each time with a different sound pressure level of the bass drum. Hip and head movements were recorded using motion capture and motion sensing. The study demonstrates that people modify their bodily behavior according to the dynamic level of the bass drum when moving to contemporary dance music in a social context. Participants moved more actively and displayed a higher degree of tempo entrainment as the sound pressure level of the bass drum increased. These results indicate that the prominence of the bass drum in contemporary dance music serves not merely as a stylistic element; indeed, it has a strong influence on dancing itself.


Author(s):  
Hadi ALIMORADI ◽  
Ruhollah FALLAH MADAVARI ◽  
Mahsa NAZARI ◽  
Reza JAFARI NODOSHAN ◽  
Mohammad Javad ZARE SAKHVIDI ◽  
...  

Introduction: Loud noise is one of the harmful factors that affects industry workers seriously. In the steel industry, a wide range of equipment and machinery are used in the production processes, which are considered as the sources of annoying noise. Sound has immediate and delayed harmful effects on the process of concentration and increases blood pressure. The aim of this study was to investigate the effect of noise in two different ranges in the control and case groups within the authorized (between 60 to 85 dB) and unauthorized (above 85 dB) categories in the steel industry. Methods: This cross-sectional study was conducted among 300 workers in Isfahan Steel Industries. Environmental sound assessment was performed to determine the distribution of sound pressure level according to the ISO 9612 standard in the company's production units. In this method, the number of exposed people, the exposure time, and the weight factor corresponding to the sound pressure level were calculated in 30 minutes. The DASS-42 and Harmon Jones (DARQ) questionnaires were used to predict the mental state of the participants and to measure the severity of mood swings and arousal. The collected data were analyzed using SPSS statistical software (ver22). Results: Based on the findings, age had a significant effect on depression, marital status had a significant effect on anxiety, and work shift had a significant effect on the level of stress and cognitive dissonance of employees. The stress mean was significantly higher in the case group (14.40 ± 1.66) than the control group (p <0.001). This indicates the effect of sound intensity level on the increase of stress and cognitive dissonance of workers in a noisy environment. With increasing exposure to sound, the participants’ stress decreased (p <0.05). Conclusion: Considering the positive and significant relationship of noise level with stress and cognitive inconsistency of workers in the case group, it is necessary to take effective preventive measures to prevent psychological harm and maintain the workers' health in this industry. In order to reduce noise, a number of applicable solutions have been proposed including spatial planning, selection of suitable materials, control of noise pollution related to outdoor construction, control of noise pollution related to indoor construction, and training.


Author(s):  
Untung Adi Santosa ◽  
Ikhsan Setiawan ◽  
B.S. Utomo

<p class="AbstractEnglish"><strong>Abstract: </strong>This paper reports the test results of a loudspeaker-based acoustic energy harvester with acoustic random noise sources from a motorcycle. The harvester consists of a quarter wavelength resonator and a subwoofer type loudspeaker with a nominal diameter of 6 inches. The motorcycle used in this experiment is 135 cc Bajaj Pulsar motorsport with modified exhaust from the GBS-Motosport Jakarta. The motor engine is operated at 3000 rpm, resulting in noise with a fluctuating Sound Pressure Level (SPL) in the range of (90-93) dB. Six variations of resonator lengths are used, those are 21 cm, 31 cm, 58 cm, 85 cm, 112 cm, and 139 cm. In this test, data of dominant frequency, SPL, and output rms voltage were taken for 15 minutes. The rms voltage is measured at 100 Ω load resistor. The results show that the 112 cm resonator produces the highest average rms electrical power, that is (0.21 ± 0.01) mW, which is obtained at frequency that fluctuates within (95-120) Hz. In addition, with random sound sources, SPL and its dominant frequency fluctuate greatly, so it will greatly affect the generated electric power. Further research is needed to enhance the output electrical power and anticipate the impact of frequency fluctuation which exists in random noise sources.</p><p class="AbstractEnglish"><strong>Abstrak: </strong>Paper ini memaparkan hasil pengujian alat pemanen energi akustik berbasis <em>loudspeaker </em>dengan sumber kebisingan acak dari mesin kendaraan bermotor. Alat pemanen energi akustik ini terdiri dari resonator seperempat panjang gelombang dan <em>loudspeaker</em> jenis <em>subwoofer</em> dengan diameter nominal 6 inci. Sumber kebisingan yang digunakan adalah motor Bajaj Pulsar 135 cc dengan knalpot modifikasi dari GBS-Motosport Jakarta. Mesin motor dioperasikan pada laju putaran tetap 3000 rpm, sehingga menghasilkan kebisingan dengan <em>SPL</em> (<em>sound pressure level</em>) yang berfluktuasi dalam interval (90-93) dB. Digunakan enam variasi panjang resonator, yaitu 21 cm, 31 cm, 58 cm, 85 cm, 112 cm, dan 139 cm. Dalam pengujian ini, data frekuensi dominan kebisingan, <em>SPL</em> kebisingan, dan tegangan keluaran alat pemanen energi akustik diambil selama 15 menit. Tegangan <em>rms</em> keluaran diukur pada resistor beban 100 Ω. Hasil eksperimen menunjukkan bahwa resonator dengan panjang 112 cm menghasilkan daya listrik <em>rms</em> rata-rata tertinggi yaitu sebesar (0,21 ± 0,01) mW, diperoleh pada frekuensi yang berfluktuasi antara 95 Hz sampai 120 Hz. Selain itu, hasil eksperimen ini menunjukkan bahwa dengan sumber bunyi acak, <em>SPL</em> kebisingan dan frekuensi dominannya sangat berfluktuasi, sehingga akan sangat berpengaruh terhadap daya listrik yang dihasilkan. Penelitian lebih lanjut diperlukan untuk meningkatkan daya listrik keluaran dan mengantisipasi dampak fluktuasi frekuensi sumber kebisingan acak.</p>


2020 ◽  
Vol 68 (3) ◽  
pp. 199-208
Author(s):  
Tomas VilniÅ¡kis ◽  
Tomas JanuÅ¡eviÄ?ius ◽  
Pranas BaltrÄ—nas

Intense sound levels produced by engineering equipment have become an acute issue. As most of engineering equipment require air supply, exhaust and good ventilation, it is not possible to control the noise by covering them with tight hoods. Louver with blades covered with acoustic materials and gaps that enable free circu- lation of air are used to this end. Three louver configurations were tested in the semi-anechoic chamber: bare metal louver blades, louver with blades covered with 20-mm-thick polystyrene foam slabs on both sides, and louver with blades covered with 15-mm-thick glass wool slab. According to the test results, louver with blades covered with glass wool slab demonstrated the best noise attenuation characteristics. The reduction of equiv- alent sound pressure level subject to blade inclination angle was from 10.8 to 12.5 dB. Sound pressure level reduction by louver with blades covered with poly- styrene foam slabs was weaker: the reduction of equivalent sound pressure level was from 5.4 to 8.4 dB. Louver with blades not covered with any acoustic material demonstrated the least noise attenuation result from 1.9 to 3.9 dB


1997 ◽  
Vol 4 (1) ◽  
pp. 39-50
Author(s):  
Michael A. Stewart ◽  
David J. MacKenzie ◽  
Robin K. Mackenzie

When impact sound tests are carried out in new and refurbished flats there is not normally a load on the floor. When the flat is occupied however, loading due to furniture, appliances, people etc, will occur which compresses the resilient layer if a floating floor construction has been used. The effect this has on impact sound insulation is considered in this paper. Impact sound transmission through a chipboard floating floor on battens supported on a concrete floor has been measured when static loads were placed on the chipboard – the loads were in the range 20 kg/m3 to 160 kg/m2. Three different resilient layers under the battens were tested: 25 mm mineral wool quilt, resilient battens and resilient battens on 13 mm mineral wool quilt. The weighted standardised impact sound pressure level (L'nTw) increased by 0.5 dB to 5 dB with the larger increases for the greater loads. Further measurements were made after the floating floors had been left under a static load of 200 kg/m2 for six months: there was an additional increase in L'nTw of 1.5 dB. Finally, measurements were compared with floors where the resilient layers had been soaked to simulate water leakage from baths, pipes etc; there was no significant difference in results.


2019 ◽  
Vol 26 (2) ◽  
pp. 109-120
Author(s):  
AM Shehap ◽  
Abd Elfattah A Mahmoud ◽  
Hatem Kh Mohamed

Nowadays, lightweight building structures are widely used by the construction industry as a more natural and cost-effective method. The purpose of this study is to compare between sound pressure level and vibration velocity method for sound reduction index determination for single- and double-leaf gypsum board partitions. The sound pressure level method was carried out according to the requirements of ISO 140-3:1997, and the vibration velocity method (V) was carried out according to some criteria of ISO 10848-1:2006. Regarding double-leaf partitions, measurements were carried out with the leaves separated by 5- and 10-cm air gaps. The effect of cavity filling with absorbing materials was studied experimentally. The space between the leaves was filled with Rockwool and polyurethane to illustrate the effect of cavity absorption on the sound reduction index behavior. It was found that there is good agreement between the two methods. Also, cavity filling with a 10-cm absorbing material such as Rockwool increases the sound reduction index at the critical frequency by 7 dB using sound pressure method and 4 dB using vibration velocity method.


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