Sound attenuation and audibility of fire alarm signal in Korean residential apartment buildings: A case study

With a view to preventing casualties due to fire outbreaks in residential buildings, we investigated the sound attenuation of audible fire-alarm signals in Korean residential apartment buildings and determine an acoustic condition for enhancing the audibility of such signals. Two sets of field measurements were performed, along with theoretical predictions using sound analysis software. In the first set of measurements, in 17 dwelling units, the standardized alarm sound level requirement of 75 dBA could not be achieved in bedrooms with existing alarm devices. In the second set of measurements, with an additional five dwelling units, both the sound attenuation according to the distance between sound sources and bedrooms and the sound insulation performance of bedroom doors were examined. The sound attenuation levels were increased by 0.72 (R² = 0.7982) and 0.48 (R² = 0.3001) dB m⁻¹ under open- and closed-door conditions, respectively. Further, the bedroom-door sound insulation performance was in the 18- to 23-dB range. Consequently, we have demonstrated that the sound power of a general residential fire alarm must be 98–107.9 dB, depending on the dwelling-unit size and floor-plan type, in order to achieve a bedroom audibility level of 75 dBA.