A survey of floor performance under impact noise and the propagation of noise withina reinforced-concrete apartment building(for national government officials and their families) was undertaken. The apartment building has five floors and 30 units. The floor plan for two units is shown in Fig.1. The floor construction in the living room which is finished with wood flooring, and in one of the six-mat Tatami rooms(No. 2) is shown in Fig.2.
In the experiment, the noise source room is in apartment No.501, and the impact noise on the floor was recorded using 5 microphones. Noise sources used were as follows :
Tapping machine(IS0 140 and JIS A1418) ....Simulating footfalls
Tire (JIS A1418) .. simulating children's jumps
The frequency spectrum ofimpact sound level in apartment No.401 are shown in Fig.3. Attenuation of impact noise of floor using soft floor-finish materials are obtained only with the tapping machine and are shown in Figs.6 and 7. Tatami and thick carpet on wood floor are better than plywood floor with respect to impact noise. The distribution of impact sound level in the apartment buiding is show in Table 3. Linear regression equations for sound pressure levels on the logarithm of distance were computed, as shown in Fig 5. The slopes ranged from -25.6 to -33.9(dB/m) for the tapping machine, and from -31.6 to -42.1(dB/m) for tire dropping.