Correlation Between Single-Number-Quantities of Impact Sound Insulation and Various Noise Ratings of Walking on Concrete Floors

The aim of this study was to investigate whether the low frequency range of 50–100 Hz should be taken into account when impact sound insulation of concrete floors is determined. Another aim was to determine the correlation between objective noise ratings of walking noise and single-number-quantities (SNQs) based on sound spectra produced by the tapping machine. Impact sound pressure levels (SPL) generated by the tapping machine on an uncovered concrete slab and on the same slab covered with eight floor coverings were measured. For each of these nine structures, eight various SNQs were calculated. The SPLs generated by three walkers wearing socks, soft-heeled shoes and hard-heeled shoes were also measured as well as noise generated by chair moving and super ball bouncing. These sounds were objectively evaluated by three noise ratings: equivalent A-weighted SPL, L _A,eq, maximum A-weighted SPL, L _A,F,max, and loudness level, L _N. At frequency bands below 100 Hz, walking with socks generated higher linear SPLs than those generated by walking with hard-heeled or soft-heeled shoes. Walking on floating floors installed on the concrete slab also generated high SPLs in the low frequency range. The noise ratings of walking with hard-heeled shoes and chair moving correlated strongly with the SNQs based on the tapping machine. However, no statistically significant correlation between the noise ratings of walking with socks and the SNQs was detected. This indicates that there is a need for a new objective SNQ in order to improve the correlation between the different walking sounds and objective rating of the concrete floors.