When public mode signaling is used to alert occupants to evacuate a building, the ANSI Audible Emergency Evacuation Signal should be used. This signal is a three-pulse temporal pattern that may be reproduced by any type of bell, horn, speaker, or other notification appliance.

The sound produced by the fire alarm system when operating in the public mode must produce a minimum sound pressure level of 15 dBA above the average ambient sound level in the area or 5 dBA above the maximum sound level that lasts 60 seconds or more, whichever is greater.

NOTE: This is an unformatted excerpt from our online fire protection training library.