Acoustic Retrofit Approach of an Apartment Living Room Using Multi-Perforated Gypsum Boards in Terms of Heavy-Weight Impact Sounds

In this study, the effects of multi-perforated gypsum boards on floor impact noises were investigated in a box-type test building and an actual apartment building. In a box-type test building with 150 mm thick slab, various design factors such as hole pattern, hole size, opening ratio, backing, or finishing materials were considered. Heavy-weight impact sources of bang machine and rubber ball were employed. The test procedure followed KS F 2810-2, and then, a single number rating was derived in accordance with KS F 2863-2. As a result, reduction of heavy-weight impact noise by applying multi-perforated gypsum boards as a ceiling material was expected maximumly up to 3 dB for bang machine and 5 dB for rubber ball. Regarding the reduction of floor impact sounds at frequencies above 125 Hz, the installed area of the employed multi-perforated gypsum board was shown as the most dominant factor. Then, an in situ investigation using standard impact sources and five children was carried out in an actual living space of an actual apartment dwelling unit. Comparing before and after installation of multi-perforated gypsum board, 1–2 dB of heavy-weight impact noises was reduced. In addition, subjective impressions of the reduced impact noise were discussed based on the field questionnaire survey using actual children’s running situations.