• Journal of the Korea Safety Management & Science
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• v.17 no.4
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• pp.97-103
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• 2015

The people who are in the noise factory are difficult to hear and recognize about fire and to evacuate quickly when a fire occurs. This study was conducted to analyze workplace's background noise of 31 factories in Incheon and to know the workplace noise level comparing to fire alarm sound level. The measured average noise level was 96.8dB(A). Noise level of measured result was exceeded as 6.8dB(A) comparing to NFSC (National Fire Safety Code) noise level of 90dB. NFPA suggests that when background noise exceeds 85dB or more than that, other methods should be considered to know alarm sound. Also fire alarm sound should exceed more than 15dB(A) comparing to background noise level. Therefore it was concluded that the design of the fire alarm systems should not be applied to the workplace without considering background noise and it needs to be improved with regulations and the systems.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.709-712
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• 2003

Recently, high noise problem was experienced during the development of 2-pole squirrel cage motor for industrial compressor. In order to firstly identify the noise characteristics, a variety of measurements were carried out. It was found out that high noise was dominated by linear and nonlinear slot noise components. For the development of low noise indusrial motor, the air gap between rotor and stator in the motor was firstly enlarged. Secondly, it was also modified for the cooling housing to have high absorption features. Consequencely, low noise 2-pole motor having the noise level of less 80㏈(A) was developed. In this paper, a series of noise identification and control process for this motor are introduced.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.214-218
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• 2003

Noise barrier is used for noise reduction method of traffic noise. The length and the total cost of that are increased in this national area. But, a maintenance management of noise barrier is not systematic, and the guideline of that is not prepared for maintenance mannual. The situations of existed installation and management of noise barriers installed at 3,619 positions were investigated by questionnarie and direct field survey. And comparisons with foreign management guideline of noise barrier were carried out. The results show that the improvement methods of maintenance management system such as practical checklist and required items for management of noise barrier were suggested.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.12
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• pp.2213-2219
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• 2008

Customer complaints on noise from the power transformer have been increased because of their concerns on environment. In order to solve fundamental noise problem of the transformer, KEPCO and domestic transformer manufacturers are developing 55 dBA class low noise transformers. To check accordance of the noise abatement law, we study relation between transformer noise level and substation border noise level. We present 'noise level of the substation border' under operating conditions and transformer noise level change. We also present an appropriate noise level of the transformer that satisfy the noise abatement law for outdoor substations.

• KIEAE Journal
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• v.2 no.1
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• pp.55-61
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• 2002

It seems inevitable for residential buildings to be high-rise and allocated near traffic roads due to the overcrowding in urban area. Acoustic environment in those residential buildings has been seriously deteriorated by the increase of traffic vehicles. Commonly used sound barriers have a limitation in controlling noise diffracted over the boundary of a sound barrier and hence are not effective to attenuate noise especially for the residential units in high level. The use of an enclosed noise barrier can be an alternative to supplement the defects of conventional noise barriers. The present work aims at providing useful data in designing enclosed noise barriers for residential areas adjacent to roads. Number of field measurements for various noise barriers and enclosed noise barriers were carried out and the results were discussed with relation to the proper design of enclosed noise barriers.

• Journal of Environmental Impact Assessment
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• v.23 no.1
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• pp.29-37
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• 2014

Exact and precise noise measurement is the basis for the reduction measure R&D, impact assessment and prediction modeling for railway noise. In this study, research trend as well as national and international noise measurement standard are investigated. For the estimation of vertical radiation characteristics of railway noise, specially devised zig was used. From the noise measurement and analysis, exact noise height radiated from the railway was characterized. The obtained results will be used for the suggestion of the height of microphone position of railway noise measurements.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.647-652
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• 2001

A noise reduction of noise barrier for high speed train was measured by using scale down model test. A selected types of noise barriers were simple vertical barrier, interference type barrier with plate, interference type barrier with cylindrical pipes. On experiment, in order to make similar present test lane condition, reduced train model and multiple noise sources were considered. As a result. interference type noise barrier with cylindrical pipes is most effective than other barriers. A present height of noise barrier which is established in a test lane is not high enough for reducing patograph noise.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1996.10a
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• pp.32-36
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• 1996

Noise radiated from refrigerator is mainly decided by compressor noise. If the compressor is silent then the refrigerator could be silent. But In some case this tendency is not true. Because there is uncertain relations between compressor noise and refrigerator noise. And the refrigerator noise is affected by the cycle-matching in the refrigerating system using compressor. In this research it was studied that the compressor noise which didn't affect some refrigerator models could affect other refrigerator models. The methods which could reduce the refrigerator noise was studied and ultimately the methods which could change the characteristics of compressor noise was presented.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.164-167
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• 2005

The noise level of refrigerating units is becoming more important to the manufacturer and the user of the product. Invariably, the compressor is a significant contributor to the overall noise level. Especially a major portion of the noise radiated by the vibration of the compressor shell. This paper presents an approach to relate the dynamic characteristics of the compressor shell with the noise radiation properties and the methods of redesigning the compressor shell to reduce the noise radiation. To relate the dynamic characteristics of the compressor shell with the noise radiation properties, the vibration and radiated sound were measured with the running compressor. Based on the results of these tests correlations between the shell vibration characteristics and the noise radiation properties are identified It was found that the vibration on the compressor shell and the noise radiated from the compressor were stronglycorrelatedincertainfrequencybands.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.349-354
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• 2005

There are various types of noise around us such as road traffic noise, aircraft noise and floor impact sound, equipment noise etc. Recently researches on the criteria to evaluate the noises have been progressed, however, researches on the noise criteria and evaluation method for the diffuser noise of HVAC are insufficient. dB(A) and NC values represented in ASHRAE guide book are applied as a noise criteria for diffuser noise, which have some problems like that the values between dB(A) and NC have deviation even if the sound is same one. Therefore, the evaluation method should be considered and proposed based on the subjective responses. From these reasons, this study aimed to analyze the evaluation factors for the diffuser noise of HVAC reflected on the subjective responses by surveying vocabularies and grouping them with factor analysis.