Multilayer elements 321
has the same stiffness as used in Figure 8.36, and the improvements are calculated using
these two pulse forms; the thin solid curves predicted for the overdamped case and the
dashed curves for the oscillatory case. For the former case, the fit between measured and
predicted data, as far as the shape of the curves is concerned, is very good, certainly in
view of the simple model used. The same comment may be made for the vinyl covering,
where a stiffness of 5.2⋅ 106 N/m is used, equivalent to a resonance frequency of
approximately 510 Hz.
We may therefore, at least for these two versions of floor covering, conclude that
the simple linear model is satisfactory when assuming critical damping or slightly more.
An absolute comparison is however not possible, due to lack of available data for the E-
modulus of these coverings.
8.5 References
EN 12354–2:2000, Building acoustics – Estimation of acoustic performance of buildings
from the performance of elements. Part 2: Impact sound insulation between rooms.
[Parts 1–3 of this standard are adopted by ISO with the number 15712 (from
2003).]
ISO 9052–1: 1989, Acoustics – Determination of dynamic stiffness. Part 1: Materials
used under floating floors in dwellings.
ISO 140–8: 1997, Acoustics – Measurements of sound insulation in buildings and of
building elements. Part 8: Laboratory measurements of the reduction of transmitted
impact sound by floor coverings on a heavyweight floor.
ISO 140–11: 2005, Acoustics – Measurement of sound insulation in buildings and of
building elements. Part 11: Laboratory measurements of the reduction of
transmitted impact sound by floor coverings on lightweight reference floors.
ISO 140–16: 2006, Acoustics – Measurement of sound insulation in buildings and of
building elements. Part 16: Laboratory measurements of the sound reduction index
improvement by additional lining.
Austnes, J. and Hveem, S. (1983) Sound insulating lightweight floating floors (in
Norwegian). Report No. 90. Norwegian Building Research Institute, Oslo, Norway.
Bies, D. A. and Hansen, C. H. (1996) Engineering noise control, 2nd edn. Spon, London.
Bodlund, K. (1987 Sound insulation of wood joist floors – rehabilitation project (in
Swedish). Report No. 54, National Swedish Institute of Building Research,
Stockholm.
Brekke, A. (1979) Sound transmission through single and double-leaf partitions (in
Norwegian). DrEng thesis, Inst. for Husbyggingsteknikk, NTH, Trondheim,
Norway.
Brouard, B., Lafarge, D. and Allard, J. F. (1995) A general method for modelling sound
propagation in layered media. J. Sound and Vibration, 183, 129–142.
Brunskog, J. (2005) The influence of finite cavities on the sound insulation of double-
plate structures. J. Acoust. Soc. Am., 117, 3727–3739.
Brunskog, J. and Hammer, P. (1999a) The interaction between the ISO tapping machine
and lightweight floors. Paper C in Licentiate thesis by Brunskog, J. Prediction of
impact sound transmission of lightweight floors. Engineering Acoustics, LTH,
Sweden. [Also published in Acta Acustica/Acustica, 89 (2003), 296–308.]
Brunskog, J. and Hammer, P. (1999b) A prediction model for the impact sound level of
lightweight floors, incorporating periodicity. Paper D in Licentiate thesis by
Brunskog, J. Prediction of impact sound transmission of lightweight floors. Engineering