Low-frequency impact sound pressure level characteristics with three standard impact sources in Korean reinforced concrete structured apartment buildings

Abstract

Floor impact sound is one of the major low frequency sound which are generated in residential buildings. In ISO standard, rubber ball standardized as heavy/soft impact source and modified tapping machine was proposed to simulate frequency characteristics of real impact sound. Rubber ball is 2.5 kg silicone rubber hollow ball and free drop from 1 m height. However, low frequency impact sound pressure level of tapping machine in a residential buildings with high floor impact isolation performance is relatively lower than real impact sound. It is need to be checked that measurement of floor impact sound isolation performance in residential buildings with resilient materials using tapping machine is suitable method. In this study, floor impact sound isolation performances of reinforced concrete structured residential buildings with resilient buildings were measured using tapping machine, bang machine and rubber ball. The low frequency measurement results were compared. It was found from measurement results that tapping machine impact sound pressure level below 100 Hz bands were lower than rubber ball and bang machine impact sound in Korean residential building where 20 mm thick resilient material was installed. Single number quantity of tapping machine impact sound pressure level in Korean residential building was 50 dB in L’n,W. From these results, it can be concluded that measurement of low frequency impact sound isolation performance using tapping machine in reinforced concrete structured residential buildings with resilient material is not suitable.