• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.11
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• pp.1001-1008
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• 2010

The architectural, facility makes the housing environment more pleasant, while too much noise coming from machinery room is detrimental to the workers physically and mentally. Therefore, more sound insulation and sound proof policies are increasingly required. However, as the annoyance caused by facility noise is influenced by various human listening characteristics as well as physical characteristics such as sound pressure level, it requires subjective evaluation characteristics through acoustic-psychological approach. For this purpose, the facility noise in the machinery room was actually measured and analyzed in the field to understand physical characteristics, and the correlation between physical evaluation value and psychological response value through listening test. Further, this study aims at presenting the data to set the standards of 'Just noticeable difference' of the facility noise together with reasonable evaluation with psychological reaction, through the grading of facility noise using trend formula. In the result, 13 stages of physical properties were forecasted for each evaluation method, together with 'Just noticeable difference' using the grading of architectural facility noise.

• Korean Journal of Occupational Health Nursing
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• v.33 no.2
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• pp.47-54
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• 2024

Purpose: This study aims to identify the level of subjective noise perception among School Meal Facility Workers and analyze the relationship between subjective noise perception and insomnia, as well as the factors affecting insomnia. Methods: School meal facility workers were surveyed from November 1 to December 31, 2021, and 717 people were selected as participants for the study. Using SPSS/WIN 25.0, t-test, x² test, and multiple logistic regression analysis were conducted. The Korean Insomnia Severity Index (ISI-K) was used to evaluate insomnia. Results: The variables that showed significant differences in insomnia in general characteristics, health-related characteristics, subjective health perception, and subjective noise perception of the study participants were mental disorders such as subjective health perception, work stress, depression, etc., gastrointestinal disorders, and subjective noise perception, among which subjective health perception, mental disorders such as depression, and subjective noise perception were analyzed as factors influencing insomnia. Conclusion: To improve the quality of insomnia and sleep among school meal facility workers, there is a need to improve healthcare, emotional management, and noisy work environments.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.10
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• pp.537-544
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• 2009

On account of the technological development, intelligent building is on increasing where the artificial regulation on indoor environment is possible, thence the concern about those facilities such as water-supply facility, water-heater and drainage facility has becomes higher. However, due to diversification and complicated system of the facility-equipments, the noise generating from such facility equipment is gradually becoming a problem, and since especially equipment noises arising at the machine room frequently infringe into the resident's pleasant living environment with the complex types of an air-borne sound and a structure-borne sound, it is becoming the civil complaint. On such viewpoint, this Study ever observed the characteristics of noise generating from various facility-equipments in the building, and intended to evaluate the facility-noises by use of the valuation index such as PSIL, N, NC, NR. As result of, the facilities noise which happens in the machine room makes normal conversation very difficult due to high sound pressure level. Based on such data, this study is willing to present it as an essential material for establishment an efficient measure against the facility-noises arising at machine room hereafter.

• Journal of Environmental Science International
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• v.8 no.4
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• pp.457-464
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• 1999

To develop managing guidance of occupational noise exposure for metal working facility, we have studied about drafting contour map of noise exposure, methods of noise assessment and actual calculation method of time weighted noise exposure. Therefore we have suggested that contour maps of noisy workplace are very important for controlling metal working fluid facility and two kinds of noise assessment method, so called, personal andstatic exposure are necessary to avoid argument between workers and managing group. Finally we would like recommend that the Korean specification of noise exposure should be modified to protect ONIHL(oocupational noise induced hearing loss).

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.7 no.4
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• pp.35-41
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• 1998

The workplace noise environment is composed of three basic elements : manufacturing (in a generic sense) facilities, office areas, and the community around the facility. Work must be done by all employees , and this involves communication within a variety of locations within the facility ; areas may be extremely noisy, moderately noisy, or quiet, such as an office. At the same time, the facility should not be annoying to the community. In this paper, the workplace environmental noise of office areas in power plant are studied. Turbine generator in power plant generates the noise of 90∼95 dB(A) in the frequency range of 1 kHz, which may cause occupational hearing loss. By abatement method which are made of isolation material and distance damping effect, about 29.5 dB(A) reduction has been obtained in office areas of the Power Plant . But, the workplace environmental noise of office areas in the power plant is not suited to office's purpose.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.134-137
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• 2014

The noise reduction performance of a passive facility is dependent on the its length or volume. In other words, this means that the larger the size of passive facility is, the better the noise reduction performance is. The sound directivity control has been proposed as an alternative for the noise reduction without a passive facility. The purpose of this study is to investigate the correlation between the flange attached to inclined exit of the tube and sound directivity when the sound radiates from the tube to the outside. As a result, the sound radiated from flanged tube had weak sound directivity in the wide angle. Also as the flange was bigger, the sound pressure level was lower in the behind the flange.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.215-218
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• 2007

In this paper, we have analyzed the effects from the change of separation distance between grounding equipment at end of telecommunication line and the inducting facilities in power inducting situation. In the result of measurement, we can see that as the separation distance between grounding equipment ant end of telecommunication line and the inducting facility become longer, the induced noise level and PIF level is decreased. From the another experiment results about the effect of changing the impedance size in both ends of telecommunication line, however, we already knew that as the ground impedance at either end of the telecommunication line become grower, the noise level is increased, and as the ground impedance at either end of the telecommunication line become smaller, the noise level is decreased. Hence we can not define the relationship exactly between separation distance from inducting facility to inducted facility and the induced noise level because when the grounding equipment is moved, its impedance size is changed too. In conclusion, changing the separation distance between grounding equipment at end of telecommunication line and the inducting facilities have not influence on the induced noise level.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.3 no.1
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• pp.20-26
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• 2000

In order to propose the design and installation information of vegetation belt, field investigation were carried out in the noise pollution control facilities of highway and the streets of a city for two years(1998~1999), and field tests were performed to analyze the noise attenuation effect of them. The noise pollution control facilities were generally classified into three types (noise barrier and vegetation belt type, mounding and vegetation belt type, vegetation belt type only). Most soundproof facilities were proved the noise reduction effects. But according to width, height, structure, auditory distance and planting forms of them, difference of noise reduction effects were investigated. The soundproof facility was suitable the mounding and vegetation belt type in the consideration of road environment, and the installation standard of vegetation was estimated that the width of vegetation was at least 20m and the length of that was 2 times in the distance from noise source.

• Journal of the Korea Safety Management & Science
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• v.22 no.2
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• pp.15-21
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• 2020

Industrial facilities need design to predict and reduce noise from design to prevent and reduce noise. The purpose of this study is to predict worker's environment and evaluate safety by analyzing noise inside underground blower room and air compressor room with fluid machinery in waste facility. This waste incineration facility was analyzed based on the ground floor, ground floor blower chamber, and air compressor chamber. The results of SPL(Sound Pressure Level) analysis at 1.5m away, which are frequently used to measure the SPL as a noise source, are as follows. SPL of basement level: 46.80[dB], SPL of ground layer: 48.57[dB]. As a result, it was expected that the noise level would be considerably lower than the 8 hours 50[dB] noise exposure per day.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.5
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• pp.502-509
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• 2010

A test facility which can simultaneously measure turbocharger operating condition variables and vibro-acoustic emission in the situations that are quite similar to real internal combustion engine operating conditions has been introduced. Using this facility, a new method sweeping from full open throttle to deep surge region along constant speed curves can be utilized instead of the stationary method that has been traditionally used to obtain turbocharger compressor maps. Data covering an extensive range of the compressor performance map have been collected and analyzed. An experimental study is performed to define a noise diagram that correlates vibro-acoustic measurements to aerothermodynamic operating conditions. An instrumentation set in the facility allows the automatic definition of the operating point on the turbine and compressor map of the turbocharger. Also, radiated sound pressure and casing vibration data corresponding to the point are obtained by a microphone in the vicinity of the compressor casing and an accelerometer on the casing. The major source(s) of noise at specific operating point on the map can be easily identified with these maps. Also, acoustic characteristics of a given turbocharger at the vicinity of the surge as well as in the surge are also defined. Finally, the possibility to define mild surge region of a turbocharger using vibro-acoustic measurements is studied.