The Role of Static Pressure and Temperature in Building Acoustics

2003 ◽  
Vol 10 (2) ◽  
pp. 159-176 ◽  
Author(s):  
Volker Wittstock ◽  
Christian Bethke
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Static Pressure ◽  
Meteorological Conditions ◽  
Pressure Level ◽  
Shell Structures ◽  
Noise Levels ◽  
Sound Pressure Levels ◽  
Sound Reduction ◽  
Reduction Index

The influence of static pressure and temperature on sound reduction indices, impact sound pressure levels, improvements of impact sound pressure levels and sound reduction indices, and relative installation noise levels is investigated. Theory revealed a systematic influence on sound reduction index and normalized impact sound pressure level. Firstly, the sound power radiated by a vibrating structure is directly proportional to the sound impedance in air and therefore to static pressure and temperature to the power of −0.5. Secondly, the sound pressure produced in a room by a sound source also depends on sound impedance, i.e. on static pressure and temperature. Since the excitation of a test specimen is not influenced by static pressure or temperature, the two effects are not compensated by any other mechanism, thus temperature and static pressure also influence sound reduction index and normalized impact sound pressure level. Experimental verification involved measurement of sound reduction index in a small test suite at static pressures between 307 and 970 hPa. Measurement results for single-shell structures showed the expected behaviour, whereas results for double-shell structures revealed a considerable scatter with a tendency towards even larger temperature and static pressure influences. For comparison of the acoustic properties of building elements, it is therefore advisable to introduce a normalized sound reduction index and a normalized impact sound pressure level, with both referred to reference conditions of static pressure and temperature. Improvements in impact sound pressure levels and sound reduction index, and relative installation noise levels are determined from changes in sound level differences. Since each difference is influenced in the same manner by meteorological conditions, the resulting improvement is independent of static pressure and temperature, as long as the differences were determined under the same meteorological conditions.

Using sound pressure level and vibration velocity method to determine sound reduction index of lightweight partitions

2019 ◽  
Vol 26 (2) ◽  
pp. 109-120
Author(s):  
AM Shehap ◽  
Abd Elfattah A Mahmoud ◽  
Hatem Kh Mohamed
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Cost Effective ◽  
Pressure Level ◽  
Vibration Velocity ◽  
Building Structures ◽  
Cost Effective Method ◽  
Cavity Filling ◽  
Sound Reduction ◽  
Reduction Index

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.

scholarly journals Status of noise pollution in urban area of Dharan Sub- Metropolitan City and Inaruwa Municipality of Sunsari District, Nepal

2017 ◽  
Vol 7 (1) ◽  
pp. 35-40
Author(s):  
Ranij Shrestha ◽  
Alankar Kafle ◽  
Kul Prasad Limbu
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pollution Assessment ◽  
Noise Pollution ◽  
Pressure Level ◽  
Noise Levels ◽  
Night Time ◽  
Level Measurement ◽  
Standard Value ◽  
Autumn And Winter

The environmental noise level measurement in Dharan and Inaruwa cities of eastern Nepal were conducted and compared with the ambient noise standards provided by Government of Nepal. The noise pollution assessment was performed in autumn and winter seasons by the indicator average day time sound pressure level (Ld, during 7.00 to 22.00 hrs) and average night time sound pressure level (Ln, during 22.00 to 7.00 hrs). The Ld and Ln values at the commercial, silence and residential zones of Dharan were 78 to 82 and 72 to 73, 65 to 73 and 60 to 70, 65 to 76 and 62 to 64 dB(A) in autumn and 78 to 79 and 72 to 76, 64 to 71 and 58 to 68, 63 to 74 and 60 to 62 dB(A) in winter, respectively whereas for Inaruwa, measurement were 75 to 77 and 73 to 75, 59 and 57, 67 and 60 dB(A) in autumn and 66 to 70 and 63 to 68, 55 and 53, 65 and 58 dB(A) in winter, respectively. The results showed that noise levels exceeded the standard value at most of the sites.

scholarly journals Investigation of Noise Pollution Distribution in Different Parts of Yazd Textile Factories

2021 ◽  
Author(s):  
Mohammad Javad Zare Sakhvidi ◽  
Hamideh Bidel ◽  
Ahmad Ali Kheirandish
Keyword(s):  
Occupational Exposure ◽  
Sound Pressure Level ◽  
Textile Industry ◽  
Sound Pressure ◽  
Noise Pollution ◽  
Sound Level ◽  
Pressure Level ◽  
Cross Sectional ◽  
Sound Pressure Levels ◽  
Different Parts

 Background: Chronic occupational exposure to noise is an unavoidable reality in the country's textile industry and even other countries. The aim of this study was to compare the sound pressure level in different parts of the textile industry in Yazd and in different parts of the textile industry. Methods: This cross-sectional study was performed on 930 textile workers in Yazd. A questionnaire was used to obtain demographic information and how to use protective equipment. Then, to obtain the sound pressure level of each unit and device and to use the measurement principles, a calibrated sound level meter was used. Then the results were analyzed using SPSS Ver.29 software. Results: The participants in this study were 714 males and 216 females with a mean age of 35.27 and 33.63 years, respectively. Seven hundred fifty-six participants (81.29%) were exposed to sound pressure levels higher than 85 dB. Among the participants, only 18.39% of the people used a protective phone permanently. Except for factory E, with an average sound pressure level of 77.78 dB, the rest of the factories had an average sound pressure level higher than the occupational exposure limit. The sound measurement results of different devices show that the sound pressure levels above 90 dB are related to the parts of Dolatab, Ring, Kinetting (knitting), Chanel, Autoconer, Dolakni, Open End, MultiLakni, Tabandegi, Texture, and Poy. Conclusion: Based on the results of the present study, noise above 90 dB is considered as one of the main risk factors in most parts of the textile industry (spinning and weaving), which in the absence of engineering, managerial or individual controls on it causes hearing loss in becoming employees of this industry

Variation in vibro-acoustic noise due to the defects in an automotive drum brake

2021 ◽  
Vol 263 (4) ◽  
pp. 2646-2653
Author(s):  
Ananthapadmanabhan Ramesh ◽  
Sundar Sriram
Keyword(s):  
Analytical Model ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Transfer Functions ◽  
Acoustic Noise ◽  
Pressure Level ◽  
Acoustic Model ◽  
Drum Brake ◽  
Non Linear ◽  
Sound Pressure Levels

Drum brakes are significant contributors to noise and vibration in automobiles causing discomfort to the passengers. The vibration and hence the resulting noise increase due to various inherent defects in the drum brake, such as asymmetry. This work aims to quantify the variation in the vibro-acoustic noise due to several common defects in the drum brake using an integrated non-linear vibration analytical model and a numerical acoustic model. The sources of vibro-acoustic noise sources such as contact and reaction forces are predicted using a four-degree-of-freedom non-linear contact mechanics based analytical model. A finite element based acoustic model of the drum brake is utilized to predict the force to the sound pressure transfer function in the drum brake. Product of the transfer functions and the forces gives the corresponding sound pressure level from which the overall sound pressure levels are estimated. The variation in the overall sound pressure levels due to different drum brake defects is evaluated by introducing defects to the analytical model. The results show that the overall sound pressure level is a strong function of the defects. It is envisioned that the current work will help in the development of effective health monitoring systems.

Gyro Rock Crusher and Asphalt Plant Sound Power Levels

2012 ◽  
Author(s):  
Henry A. Scarton ◽  
Kyle R. Wilt
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Low Frequency ◽  
Pressure Level ◽  
Sound Power ◽  
Far Field ◽  
Atmospheric Attenuation ◽  
Frequency Sound ◽  
Sound Pressure Levels ◽  
Rock Crusher

Sound power levels including the distribution into octaves from a large 149 kW (200 horsepower) gyro rock crusher and separate asphalt plant are presented. These NIST-traceable data are needed for estimating sound pressure levels at large distances (such as occurs on adjoining property to a quarry) where atmospheric attenuation may be significant for the higher frequencies. Included are examples of the computed A-weighted sound pressure levels at a distance from the source, including atmospheric attenuation. Substantial low-frequency sound power levels are noted which are greatly reduced in the far-field A-weighted sound pressure level calculations.

Case study: Evaluation of noise reduction in frequencies and sound reduction index of construction with variable noise isolation

2020 ◽  
Vol 68 (3) ◽  
pp. 199-208
Author(s):  
Tomas VilniÅ¡kis ◽  
Tomas JanuÅ¡eviÄ?ius ◽  
Pranas BaltrÄ—nas
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Glass Wool ◽  
Noise Attenuation ◽  
Engineering Equipment ◽  
Sound Levels ◽  
Air Supply ◽  
Study Evaluation ◽  
Sound Reduction

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

scholarly journals Noise Emissions in Milking Parlours with Various Construction Solutions

2016 ◽  
Vol 19 (2) ◽  
pp. 49-51
Author(s):  
Marie Šístková ◽  
Martin Pšenka ◽  
Ivo Celjak ◽  
Petr Bartoš ◽  
Štefan Mihina ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Noise Exposure ◽  
Pressure Level ◽  
Different Types ◽  
Sound Pressure Levels ◽  
Mechanical Devices

Abstract Mechanical devices in parlours are a source of noise, and this noise has an effect not only on the operators of the parlour but also on dairy cows. They have more sensitive hearing than humans. The aim of this article was to analyse the sound pressure level and determine the noise exposure of dairy cows at different technological solutions of milking parlours, during their day routine. In the experiment, tandem, herringbone and rotary milking parlours were used. Noise exposure was measured during the milking process. After evaluation of noise pressure levels of different types of milking parlours, it can be concluded that in this experiment, the equivalent noise pressure level was lowest in the tandem milking parlour. Equivalent sound pressure levels in the rotary and herringbone milking parlour were almost about the same values. These values are higher than values in the tandem milking parlour, about 10 decibels. The differences within mean LAFeq values between the herringbone milking parlour and tandem milking parlour were highly statistically significant (P <0.001***).

scholarly journals Experimental study of aerodynamic noise performance of improved air distributor for ships

2021 ◽  
Vol 13 (3) ◽  
pp. 168781402110012
Author(s):  
Yuejiao Guo ◽  
Guozeng Feng ◽  
Shuya Lei ◽  
Bo Meng ◽  
Yang Xu
Keyword(s):  
Flow Rate ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Static Pressure ◽  
Resistance Coefficient ◽  
Pressure Level ◽  
Channel Structure ◽  
Aerodynamic Noise ◽  
Frequency Noise ◽  
Reduction Effect

In ships, aerodynamic noise from the variable-air-volume fan is a common problem. This study experimentally explores the strategy of reshaping the traditional C-shaped channel structure to an L-shape to reduce noise. The noise level and resistance coefficient of the improved air distributor are analysed, and the results show that the noise of the original air distributor is 56.3 dB(A) under the rated working conditions (static pressure of 800 Pa and flow rate of 350 m3/h), which exceeds the International Maritime Organisation’s (IMO) ship noise limit (55 dB(A)). For the improved air distributor, the noise pressure level is 38.5 dB(A), the sound pressure level of high-frequency noise is reduced by 48% and the peak sound pressure level appears at 125 to 250 Hz, a frequency below the threshold of human hearing. Thus, the reshaping of the channel has a significant noise reduction effect. When the static pressure is 400 Pa and the flow rate is 100 to 500 m3/h, the sound pressure level of the improved air distributor is reduced by 29.9% to 32.2% to become less than 55 dB(A). Thus, the sound pressure level at the outlet of the improved air distributor meets the IMO ship noise standard.

scholarly journals Mitigasi dampak kebisingan bandara terhadap kehidupan pemukiman sekitar bandara SSK II Pekanbaru

Jurnal Zona ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 91-106
Author(s):  
Eko Hendi Saputra ◽  
Yusni Ikhwan Siregar ◽  
Hafidawati Hafidawati
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Noise Exposure ◽  
Pressure Level ◽  
Noise Attenuation ◽  
Residential Areas ◽  
Noise Levels ◽  
Residential Communities ◽  
The People ◽  
The Impact

This study aims to determine the level of noise caused by flight activities at Sultan Syarif Kasim II Airport Pekanbaru, analyze noise levels that occur due to flight activities at Sultan Syarif Kasim II Airport Pekanbaru and analyze efforts to control the negative impact of airport noise on the living environment of community settlements. around Sultan Syarif Kasim II Airport Pekanbaru. This research uses field observation method, which is making direct observations at the research location by looking at the condition of the location and the suitability of the location which is the sampling point of the study (the noise level boundary at Sultan Syarif Kasim II Airport). Observations were made for 16 hours (Ls) at an interval of 06.00 - 22.00. Measurement of sound pressure level is carried out on holidays (Sunday) and weekdays (Monday), which starts on November 1, November 2, November 8, and November 9, 2020, which is carried out in residential areas around Sultan Syarif Kasim II Airport Pekanbaru, which are spread across 6 measurement points where the measurement of sound pressure level is done in duplicate, namely: Jl. Kaswari (point 1), Jl. Rawa Indah II (Point 2), Jl. Rawa Indah III (Point 3), Jl. Cinnamon (Point 4), Jl. Pahlawan Kerja gg.Pala 49 (Point 5) and Jl. Nur Asiyah (Point 6) The results of the processing of noise measurement data were made of a mapping model using surfer 11 software and to clarify the noise description at the sampling location, the map of the results of surfer 11 software processing was plotted on the airport area map.     Based on the results of measurements of noise levels around Sultan Syarif Kasim II airport, it is known that the location of point 1 (Jl. Rawa Indah II) experienced the highest noise exposure. These results indicate the location of point 1 should receive serious attention for the people who live around the airport, because the impact of airport noise has the potential to negatively affect the lives of residential communities. From the observations, it was also known that the level of noise attenuation was still low, both in terms of trees around the settlement and height, walls and fences were still not effective at reducing noise.         Based on the results of measurements of noise levels around Sultan Syarif Kasim II airport, it is known that the location of point 1 (Jl. Rawa Indah II) experienced the highest noise exposure. These results indicate that the location of point 1 should receive serious attention for the people who live around the airport, because the impact of airport noise has the potential to negatively affect the lives of residential communities. From the observations, it was also known that the level of noise attenuation was still low, both in terms of trees around the settlement and height, walls and fences were still not effective at reducing noise.         From the results of the research that has been done, several mitigation strategies can be formulated to reduce noise levels around Sultan Syarif Kasim II airport. Planting plants in accordance with the needs of controlling or reducing noise in human settlements. Tree categories suitable for planting in residential areas around the airport are: shady trees that can be planted tightly or with lots of leaves that can grow to a height of about 4 - 15 m (such as acacia, mahogany, flamboyant, ironwood or banyan trees, bamboo or cypress)

scholarly journals “Horário do Soninho”: uma estratégia para reduzir os níveis de pressão sonora em uma unidade de terapia intensiva neonatal

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Adriana Duarte Rocha ◽  
Patricia Miranda Sá ◽  
Danielle Bonotto Cabral Reis ◽  
Ana Carolina Carioca Costa
Keyword(s):  
Intensive Care ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Quiet Time ◽  
Cross Sectional ◽  
Significant Difference ◽  
Sound Pressure Levels ◽  
Terapia Intensiva ◽  
Tiempo De Silencio

ResumoIntrodução: Estudos mostram que o ambiente muito estimulante, com altos níveis sonoros, interfere negativamente no desenvolvimento e crescimento de recém-nascidos. Objetivo: verificar se o "horário do soninho" é capaz de reduzir os níveis de pressão sonora em uma unidade de cuidados neonatais. Método: Trata-se de uma pesquisa transversal. A medida do nível de pressão sonora foi realizada durante 15 dias não consecutivos, com tempo de avaliação de 30 minutos antes, 1 hora durante e 30 minutos após o "horário do soninho" Resultado: Observamos uma redução dos níveis de pressão sonora durante o "horário do soninho" (p = 0,00). Essa redução permaneceu no período dos 30 minutos subsequentes, com diferença estatisticamente significante quando comparada ao período antes do "horário do soninho" (p = 0,00). Conclusão: O "horário do soninho" é uma ferramenta capaz de reduzir o nível de pressão sonora em uma unidade de terapia intensiva neonatalPalavras-Chave: ruído; Terapia Intensiva neonatal; Recém-nascido AbstractBackground: Studies show that super stimulating environment, with high sound levels, that negatively interfere in the development and growthof newborns. Aim:  Verify if the "quiet time" is able to reduce the sound pressure levels in a neonatal care unit. Method: It is a cross-sectional research. The measurement of the sound pressure level was performed during 15 non-consecutive days with an evaluation time of 30 minutes before, 1 hour during and 30 minutes after the "quiet time" Result: We observed a reduction of the sound pressure levels during the hours of quiet time (p = 0.00). This reduction remained in the period of the subsequent 30 minutes, with a statistically significant difference when compared to the period before sleep time (p = 0.00). Conclusion: The “quiet time is a tool capable of reducing sound pressure level in a neonatal intensive care unitKey Words: noise; Intensive Care, neonatal; Infant, newborn Resumen"Tiempo de silencio": una herramienta para reducir los niveles de presión acústica en una unidad de cuidados intensivos neonatalesAntecedentes: los estudios muestran que el entorno súper estimulante, con altos niveles de sonido, interfiere negativamente en el desarrollo y crecimiento de los recién nacidos. Objetivo: Verificar si el "tiempo de silencio" puede reducir los niveles de presión acústica en una unidad de cuidados neonatales. Método: es una investigación transversal. La medición del nivel de presión sonora se realizó durante 15 días no consecutivos con un tiempo de evaluación de 30 minutos antes, 1 hora durante y 30 minutos después del "tiempo de silencio" Resultado: Observamos una reducción de los niveles de presión sonora durante las horas de tiempo de silencio (p = 0.00). Esta reducción se mantuvo en el período de los siguientes 30 minutos, con una diferencia estadísticamente significativa en comparación con el período anterior al tiempo de sueño (p = 0,00). Conclusión: el “tiempo de silencio es una herramienta capaz de reducir el nivel de presión acústica en una unidad de cuidados intensivos neonatales Palabras clave: ruido; Cuidados Intensivos, neonatales; Infante, recién nacido

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