UA-74950034-1
Ugunsdzēsības sistēmas


fire alarm system is number of devices working together to detect and warn people through visual and audio appliances whensmokefirecarbon monoxide or other emergencies are present. These alarms may be activated from smoke detectors, and heat detectors. Alarms can be either motorised bells or wall mountable sounders or horns. They can also be speaker strobes which sound an alarm, followed by a voice evacuation message which usually state in the lines of "Attention, Attention. A fire emergency has been reported. Please leave the building via the nearest exit. DO NOT use elevators!" They may also be activated via Manual fire alarm activation devices such as manual call points or pull stations. 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 inEurope sound like a siren with alternating frequencies. Fire alarm sounders in the United States can be either continuous or set to different codes such as Code 3. Fire alarm warning devices can also be set to different volume levels. Smaller buildings may have the alarm set to a lower volume and larger buildings may have alarms set to a higher level.

Parts

Fire alarm control panel (FACP) AKA fire alarm control unit (FACU); This component, the hub of the system, monitors inputs and system integrity, controls outputs and relays information.

    • Primary power supply: Commonly the non-switched 120 or 240 volt alternating current source supplied from a commercial power utility. In non-residential applications, a branch circuit is dedicated to the fire alarm system and its constituents. "Dedicated branch circuits" should not be confused with "Individual branch circuits" which supply energy to a single appliance.
    • Secondary (backup) power supplies: This component, commonly consisting of sealed lead-acid storage batteries or other emergency sources including generators, is used to supply energy in the event of a primary power failure.
    • Initiating devices: This component acts as an input to the fire alarm control unit and are either manually or automatically activated. Examples would be devices pull stations, heat detectors, or smoke detectors. Heat and smoke detectors have different categories of both kinds. Some categories are beam, photoelectrical, aspiration, and duct.Notification appliances: This component uses energy supplied from the fire alarm system or other stored energy source, to inform the proximate persons of the need to take action, usually to evacuate. This is done by means of a flashing light, strobe light, electromechanical horn, "beeper horn", chime, bell, speaker, or a combination of these devices. The System Sensor Spectralert Advance Horn makes a beeping sound and electromechanical sound together. Strobes are either made of a xenon tube (most common), or now LED lights.
    • Building safety interfaces: This interface allows the fire alarm system to control aspects of the built environment and to prepare the building for fire, and to control the spread of smoke fumes and fire by influencing air movement, lighting, process control, human transport and exit.

Initiating devices

    • Manually actuated devices; also known as fire alarm boxes, manual pull stations, or simply pull stations, Break glass stations, call points or Buttons. Devices for manual fire alarm activation, are installed to be readily located (near the exits), identified, and operated.
    • Automatically actuated devices can take many forms intended to respond to any number of detectable physical changes associated with fire: convected thermal energy; heat detector, products of combustion; smoke detector, radiant energy; flame detector, combustion gasses; fire gas detector, and release of extinguishing agents; water-flow detector. The newest innovations can use cameras and computer algorithms to analyze the visible effects of fire and movement in applications inappropriate for or hostile to other detection methods.