• Proceedings of the Korean Society of Marine Engineers Conference
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• 2002.05a
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• pp.209-212
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• 2002

This article introduce Comfort Class V released by Dnv The Class has an objective of classifying ships by noise and vibration levees. It is apparent that noise criteria listed in the Class can not be satisfied without special efforts to enhance sound insulation performance in cabins. Accordingly, panel makers should develope panels which have very high sound insulation performance enough to satisfy the criteria. Also, due to large difference of sound insulation performance between cabin and laboratory, it is necessary that ship yards should improve the method for installing cabins.

• The Journal of the Acoustical Society of Korea
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• v.38 no.4
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• pp.396-405
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• 2019

The speech privacy of closed office rooms located in a university campus was measured and assessed in terms of SPC (Speech Privacy Class) values. The measurements of two quantities, the LD (Level Difference) between a source and a receiving room, and the background noise level ($L_b$) at the receiving room were carried out in 5 rooms located in 3 different buildings in the university campus. Each of the 5 rooms was adjacent to both offices and corridors through walls. The TL (Transmission Loss) between the source and the receiver room was also measured to compare the difference of two standard methods, ASTM E2836-10 and KS F 2809. The present results show that the speech privacy of the 5 office rooms is not met the requirement for a minimum SPC values of 70. A minimum LD value of 41 dB between the source and the receiver room should be achieved for having a SPC value of 70 when the mean measured value of $L_b$ at the receiving room is 29.2 dB. That is, the TL(avg) value averaged over the octave bands from 160 Hz to 5000 Hz between the source and the receiver room should be or greater than 40 dB. The most important architectural factor influencing the LD value is the presence of openings, such as doors, and windows, on the adjacent walls between the source and receiving room. Therefore, if the opening of the adjacent wall is replaced by an opening with high sound insulation, the appropriate SPC value of the research and office rooms can be achieved.