Abstract

Acoustic alarms must be effective even in noisy workplaces characterized by high reverberation. This project, by identifying the type of acoustic alarms that are the most audible in industrial settings, was to allow designers, producers and users to ensure that acoustic alarms remain effective. A computerized model of sound propagation and human sound tests have led to the development of design rules that are compatible with noisy and high-reverberation workplaces. The researchers recommend using signals with different spectral features within a frequency range of 300 to 3,000 Hz and to completely avoid pure sounds. It is also preferable to use sirene frequency modulation signals, which are more resistant to acoustic variations caused by sound reverberation. If necessary, pulsed signals can be used, but they must involve very distinct rhythmic sequences and minimum distance between the source of the alarm and the workers.