Practical example 1: Spatial performance for audible notification.

The perception of acoustic signaling devices is determined by many factors. In particular, ambient noise and the use of hearing protection must be taken into account. 3D-Coverage shows why.

SOUNDERAMBIENT NOISELENGTHWIDTHHEIGHT3D-COVERAGE
Pfannenberg
PA 1 100 dB(A)
65 dB29 m25 m29 m21,025 m³
70 dB16 m14 m16 m3,584 m³
75 dB9 m8 m9 m648 m³
80 dB5 m4,5 m5 m113 m³
85 dB3 m2,5 m3 m23 m³

Ambient noise can influence safety.

Whether or not the audible signal from a sounder is successfully perceived is not just dependent on the output sound level generated and technology used to create the alarm signal. Ambient noise levels and sounder placement location are crucial elements that should not be overlooked.

The adjacent example illustrates the effect on coverage volume of an 100 dB(A) audible signaling device due to a 10 dB(A) change in ambient noise level. Increasing from 75 dB(A) to 85 dB(A) shows that the warning signal will not be successfully perceived.

The 3D-Coverage values show that the effective covered area is significantly reduced when the ambient noise level rises. If the alarm system designer does not take all aspects into consideration, the consequences can spell danger for people in the surrounding area.