Journal of the Korean Wood Science and Technology

The Korean Society of Wood Science & Technology (한국목재공학회)
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Sound Absorption Coefficient and Sound Transmission Loss of Rice Hull Mat

  • Kang, Chun-Won (Department of Housing Environmental Design, and Research Institute of Human Ecology, College of Human Ecology, Chonbuk National University) ;
  • Lee, Nam-Ho (Department of Wood Science & Technology, College of Agriculture & Life Sciences, Chonbuk National University) ;
  • Jang, Sang-Sik (Department of Forest Products, College of Agriculture & Life Sciences, Chungnam National University) ;
  • Kang, Ho-Yang (Department of Forest Products, College of Agriculture & Life Sciences, Chungnam National University)
  • Received : 2019.02.08
  • Accepted : 2019.05.02
  • Published : 2019.05.25
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Abstract

The sound absorption coefficient and transmission loss of several types of rice hull mats with varying apparent densities and thicknesses are estimated in this paper using the transfer function and matrix methods, respectively, to evaluate the possibility of using rice hull as an acoustic construction material. The mean sound absorption rates of 10-cm-thick rice hull mats with target densities of $0.10g/cm^3$, $0.12g/cm^3$, and $0.14g/cm^3$ were 0.91, 0.92, and 0.95, respectively, while those of the 1-cm-thick plywood attached to the back of the rice hulls were 0.90, 0.92, and 0.92, respectively. The means of the sound transmission loss of the 10 cm-thick rice hull mats with the target densities of $0.10g/cm^3$, $0.12g/cm^3$, and $0.14g/cm^3$ were 7.66 dB, 10.49 dB, and 14.14 dB, respectively, while those of the 1 cm-thick plywood attached to the back of the rice hulls were 33.34 dB, 36.72 dB, and 38.95 dB, respectively. In conclusion, a rice hull mat could be used as acoustic construction materials because of its high sound absorption coefficient and sound transmission loss.

Keywords

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Fig. 1. Impedance tube for measuring sound transmission loss ratio (kang et al., 2018b).

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Fig. 2. Sample preparation for measuring sound absorption ratio and sound transmission loss.

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Fig. 3. Sound absorption rate of rice hull mat with apparent density of 0.10 (Graph legend values denote sample thickness).

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Fig. 4. Sound absorption rate of rice hull mat with apparent density of 0.12 (Graph legend values denote sample thickness).

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Fig. 5. Sound absorption rate of rice hull mat with apparent density of 0.14 (Graph legend values denote sample thickness).

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Fig. 6. Sound absorption rate of 1 cm thick plywood attached rice hull mat with apparent density of 0.10 (Graph legend values denote sample thickness).

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Fig. 7. Sound absorption rate of 1 cm thick plywood attached rice hull mat with apparent density of 0.12 (Graph legend values denote sample thickness).

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Fig. 8. Sound absorption rate of 1 cm thick plywood attached rice hull mat with apparent density of 0.14 (Graph legend values denote sample thickness).

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Fig. 9. Sound transmission loss of 10 cm thick rice hull mat (Graph legend values denote apparent density of rice hull mat).

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Fig. 10. Sound transmission loss of 1 cm thick plywood attached 10 cm thick rice hull mat (Graph legend values denote apparent density of rice hull mat).

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