A Field Measurement Study on the Sound Attenuation of Fire Alarm Signals in Apartment Buildings

Abstract

The aim of this study is to investigate the sound attenuation of the fire alarm signals in the dwelling units of apartment buildings. Two field measurements were carried out. The first measurements were examined the sound attenuation from the common corridors to the bedrooms(main room). There were conducted under two volume conditions which were generated about 90 dBA and 115 dBA in common corridor using fire alarm bell. In the second measurements, the sound attenuation from the living rooms to the bedrooms were investigated. There were performed that a total of six alarm signals such as fire alarm bell, buzzer, reverse alarm, slow whoop, T-3 and white noise were used and they were generated about 90 dBA in living rooms. The results of the first measurements showed that the A-weighted SPLs in bedrooms were 38.1 - 46.8 dBA when the fire alarm bell was generated 115 dBA. Moreover, the SPLs indicated 21.4-30.2 when it was generated 90 dBA. It was confirmed that fire alarm device located in corridor was not invalid compared to the minimum sound level of 75 dBA. The results of second measurements presented that the SPLs were approximately increased by 36 dBA with only moving fire alarm device from corridor to living room. Moreover, the T-3 alarm signal had a high level at 500 Hz and was relatively low the sound attenuation between the living rooms and the bedrooms compared to the six alarm sources. In this study, therefore, it was determined that T-3 was best source in term of the sound propagation. However, SPLs by all alarm signals still did not satisfy 75 dBA in bedrooms.