Fire alarm system

Automatic initiating devices may use cameras and computer algorithms to analyze and respond to the visible effects of fire and movement in applications inappropriate for or hostile to other detection methods.

Fire alarm sounders can be set to certain frequencies and different tones, either low, medium, or high, depending on the country and manufacturer of the device.

Fire alarm electronic devices are known as horns in the United States and Canada and can be continuous or set to different codes.

Notification appliances utilize audible, visible, tactile, textual or even olfactory stimuli (odorizers)[15][16] to alert the occupants of the need to evacuate or take action in the event of a fire or other emergency.

Voice alarm systems are typically used in high-rise buildings, arenas, and other large "defend-in-place" occupancies such as hospitals and detention facilities where total evacuation is difficult to achieve.

[citation needed] Voice-based systems allow response personnel to conduct orderly evacuation and notify building occupants of changing event circumstances.

[citation needed] Audible textual appliances can be employed as part of a fire alarm system that includes EVAC capabilities.

From these control locations, trained personnel activating and speaking into a dedicated microphone can suppress the replay of automated messages to initiate or relay real-time voice instructions.

[citation needed] In the United States, fire alarm evacuation signals generally consist of a standardized audible tone, with visual notification in all public and common-use areas.

Legacy systems, typically found in older schools and buildings, have used continuous tones alongside other audible notifications.

In the United Kingdom, fire alarm evacuation signals generally consist of a two-tone siren with visual notifications in all public and common-use areas.

In the United States, a residential fire alarm system is required in buildings where more than 12 smoke detectors are needed.