Analysis of Sound Pressure and Frequency Characteristics of Fire-Alarm Bells and Electronic Sirens

In the event of fire, how quickly occupants can hear, see, and/or smell the fire and then exit the building are important for reducing the number of potential casualties. After a person or an automatic fire-detection system detects a fire, an installed emergency alarm system is used to alert building occupants about the fire. The emergency alarm system plays an important role in alerting the occupants to the fire by emitting a high-pitched sound when the fire is initially detected. Although bells and electronic sirens can both be used in fire-alarm systems, usually only bells are used in most commercial fire alarms except for a few fire extinguishers. Recently, however, the development of circuit integration technology and subsequent competitive pricing and improved performance have fostered an environment favorable for the widespread application of electronic sirens. However, because electronic sirens that emit various sounds will likely confuse building occupants used to hearing familiar-sounding conventional fire-alarm bells, electronic sirens must be engineered to sound like conventional fire-alarm bells. Therefore, in this study, experiments were conducted to measure the specific sound pressure and frequency characteristics of commercially available fire-alarm bells and electronic sirens, and their characteristics were reviewed. In addition, the differences between the bells and sirens were analyzed to develop a plan for supplementing warning sounds of electronic sirens.