4.5 Buzzers for smoke alarm
UL-217 performance requirements of smoke alarm define the SPL needs to achieve at least 85dB@3M with frequency no higher than 3.5KHz. People can detect sounds in a frequency range from about 20Hz ~ 20 kHz and most sensitive range is 2KHz ~ 5KHz, but we lose some high-frequency sensitivity as we mature. Seniors may not hear the alarm if the frequency is too high.
The SPL of buzzer will be tested separately to confirm its performance. After installing the buzzer the smoke alarm, it will be tested by certificated lab.