A fire alarm system warns people when smoke, fire, carbon monoxide or other fire-related emergencies are detected. These alarms may be activated automatically from smoke detectors and heat detectors or may also be activated via manual fire alarm activation devices such as manual call points or pull stations. Alarms can be either motorized bells or wall mountable sounders or horns. They can also be speaker strobes which sound an alarm, followed by a voice evacuation message which warns people inside the building not to use the elevators. Fire alarm sounders can be set to certain frequencies and different tones including low, medium, and high, depending on the country and manufacturer of the device. Most fire alarm systems in Europe sound like a siren with alternating frequencies. Fire alarm electronic devices are known as horns in the United States and Canada and can be either continuous or set to different codes. Fire alarm warning devices can also be set to different volume levels.
There are two types of fire alarm initiating devices: manual and automatic.
• Manual initiating devices are manual pull-down stations that can only be activated by hand. …
• Automatic initiating devices trigger automatically in the presence of fire.
• Automatic fire alarm systems are activated through fire detectors, such as smoke or heat sensors. Manual fire alarms are activated with manual call points or pull stations. There is no reason for a fire alarm system to exclude one or the other. Both can be included in the same system.