• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.1
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• pp.53-61
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• 2015

This paper reports the test results of the floating floor system used to reduce the floor noise of apartment buildings. Recently, many soft resilient materials placing between the reinforced concrete slab and finishing mortar are used. The resilient material should not only reduce the floor impact sound vibration from the floor but also support the load on the floor. Thus, even if soft resilient materials satisfy the maximum limitation of light-weight impact sound and heavy-weight impact sound, these materials may not support the load on the floor. The experimental program involved conducting sixteen sound insulation floating floor specimens. Three main parameters were considered in the experimental investigation: resilient materials, loading location, and layers of floor. Experimental results indicated that the stiffness of resilient material significantly influenced on the structural behavior of floating floor system. In addition, the deflection of the floating concrete floor loaded at the side or coner of the specimen was greater than that of the floor loaded at the center of the specimen. However, the aerated concrete did not effect on the cracking strength of floating floor system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.351.2-351
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• 2002

The overall noise reduction was compared in regard to the vibrational characteristics of floor impact noise in a multi story residential building which has several noise reduction treatments. The vibration through its structural elements such as wall, floor and ceiling and sound emitting were investigated for each insulation treatment. It was found that, in case of heavy-weight impact noise, the vibration energy is emitted mostly from ceiling, but for the light-weight impact noise, most of the energy comes through ceiling and walls. (omitted)

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.8
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• pp.651-658
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• 2014

Notification 2013-611 of MOLIT has come into effect. It relates primarily to new standard impact source. In this study, an in-depth experimental analysis of the difference between a bang machine and an impact ball was performed via field testing of shear wall and flat plate structure at 51 sites. This paper focuses on the difference in single number quantities between a bang machine and an impact ball. At wall thicknesses of 180 and 210 mm in shear wall structure, the single number quantities exhibited differences of 3.1 and 4.5 dB, respectively, and at thicknesses exceeding 250 mm in flat plate structure, the difference was constant at 4.6 dB. With regard to flat plate structures, the single-index difference increased up to 11 dB as the thickness of the floor slab increased. In general, the highest level of contribution for the bang machine was 63 Hz, irrespective of thickness determining bandwidth. The highest level for the impact ball were 63 Hz and 125 Hz. In future research, when reviewing additional field performance measurement data, it will be necessary to consider a detailed examination instead of the current method of uniformly adding 3 dB for all thicknesses and types of structures.

• Elastomers and Composites
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• v.49 no.2
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• pp.95-102
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• 2014

The noise between floors of apartment has been hot issue nowadays. In order to improve the noise insulation performance, we proposed the antivibration rubber system which can be applied to the floor system for sound insulation. Among various types of elastomer, butyl rubber showed the good aging characteristic, low rebound resilience and high damping factor. Thus, the butyl rubber was selected as a basic rubber for antivibration rubber system. The effects of type and loading amounts of carbon black on antivibration properties of butyl rubber were studied. The increase of surface area and the content of carbon black resulted in high bound rubber fraction, high mechanical property, low rebound resilience, and high damping factor of butyl rubber. Based on the results of this study, the new antivibration rubber was prepared and applied to the floor system for sound insulation. The impact sounds of floor system proposed in this study were 40 dB and 43 dB in cases of light weight and heavy weight impact sound, respectively.

• The Journal of the Acoustical Society of Korea
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• v.42 no.6
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• pp.572-583
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• 2023

Demand for wood in construction is increasing worldwide. In Korea, technical reviews of high-rise Cross Laminated Timber (CLT) buildings are under way. In this paper, Floor Impact Sound Insulation Performance (FISIP) and Transmission Loss (TL) of 150 mm thick CLT floor panels made of two domestic species, Larix kaempferi and Pinus densiflora, are investigated. The CLT slabs were tested in reverberation chambers connected vertically. When comparing Single Number Quantity (SNQ) of FISIP of the bare panels, the Larix CLT is 3 dB lower in heavy-weight and 1 dB in light-weight than the Pinus CLT. However, there was no difference when concrete toppings were added to improve the performance. As the concrete toppings became thicker, the heavy-weight was reduced by 9 dB ~ 20 dB, and the light-weight by 20 dB ~ 30 dB. And the analysis of these results with area density has confirmed that the area densities are highly correlated (R² = 0.94 ~ 0.99) to the FISIP of the CLT. The types of CLT didn't affect the TL. Comparison of theoretical TL values with measured TL values has shown that the frequency characteristics are similar but 8 dB ~ 12 dB lower in measured values. The relationship between the TL and frequency characteristics of the tested CLT slabs was derived by using the correction value.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.250-251
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• 2010

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.461-468
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• 2002

Prediction method of floor impact noise for light and heavy weight impact is described. Sound pressure level is predicted based on the impedance method. For floating floor system, noise reduction is studied assuming 1-D mass-spring system. It is found that comparisons of predictions and measurements show good agreements. However, certain correction factor is needed to predict noise reduction of floating floor system.

• The Journal of the Acoustical Society of Korea
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• v.25 no.2
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• pp.49-55
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• 2006

Measurement of impact sound insulation of floor, by current Korean Standard KS F 2810-2. is to be made with peak levels over 4 point in a receiving room. But it is often the case that there is inconsistency in results at various receiving points in the receiving room. Such variations obviously have effects on the repeatability and reproducibility of measured data. The result shows that there are even 10 dB deviations in 63Hz octave band frequency range and relatively less variations are occurred in other low frequency ranges. Such variations seems to be coming from modal overlaps of the receiving room. According to current rating method of floor impact sound. KS F 2863-2, that may affect on the single number latins scheme. From the result of tests in this study, there are 2dB to 6dB differences in the sin91e number with the combination of measurement points. This means that the reduction of measurement variations from the microphone positions is needed for a better credibility of measurement results.

• The Journal of the Acoustical Society of Korea
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• v.27 no.4
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• pp.163-170
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• 2008

Most of receiving rooms for the measurement of floor impact sound have rectangular shapes with couple of meters of dimension, with reflective finishing, no furniture, no curtains. Modal overlaps in those condition are the major reason for the low reproducibility, and as a matter of course, the low credibility. It is the major purpose of this study that searching for a better measurement method which mitigate the effect of modal overlap on measurement. Two ways of methods are tested. One is the way described in ISO standards which enables controlling the room modes of receiving rooms, the other is the way which enables to get more precise spatial averages in receiving rooms with room modes. It is not easy maintaining the reverberation time of low frequency bands in the range between 1s and 2s, though it is proven to be effective controlling the room modes with base traps. Space-time average SPL's through combinations of rotating microphones are easy to measure, and have good consistencies with average SPL of entire receiving room.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.586-591
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• 2002

Recently, the research and discussion to set up the evaluation standard for nor impact noises in multistory residential buildings has been vividly carried out In Korea. Therefore, the correlation between the methods and auditory responses was investigated through this research to investigate the applicability of the L index evaluation method and the reverse A characteristics evaluation method that are listed in JIS A 1419 since Japanese circumstance are similar to Korean after evaluating the duality of Korean multistory residential buildings. As a result, it was found that the correlation between the value resulted from L index evaluation and the value from reverse A characteristics evaluation is high. In addition, it was also revealed that human responses to each Impacter was similar. Consequently, it is considered th:31 the tendency about the two methods would be similar.