Alarms can be either motorized bells or wall mountable sounders or horns. Fire alarm sounders can be set to certain frequencies and fire service manual volume 1 pdf tones including low, medium and high, depending on the country and manufacturer of the device.
Fire alarm warning devices can also be set to different volume levels. Equipment specifically manufactured for these purposes is selected and standardized installation methods are anticipated during the design. In Canada, the ULC is the standard for the fire system. It is a standard widely used around the world. 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. 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. The batteries can be either inside the bottom of the panel or inside a separate battery box installed near the panel. Initiating devices: These components act as inputs to the fire alarm control unit and are either manually or automatically activated. Examples would be devices such as pull stations, heat detectors, and smoke detectors.
Heat and smoke detectors have different categories of both kinds. Some categories are beam, photoelectric, ionization, 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 pulsing incandescent light, flashing strobe light, electromechanical horn, electronic horn, chime, bell, speaker, or a combination of these devices. 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.
They are usually actuated by means of physical interaction, such as pulling a lever or breaking glass. 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, such as the Fike Corporation’s Signifire system. Evacuation signals may consist of simple appliances that transmit uncoded information, coded appliances that transmit a predetermined pattern, and or appliances that transmit audible and visible textual information such as live or pre-recorded instructions, and illuminated message displays. 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. Emergency signals are intended to be distinct and understandable to avoid confusion with other signals. As per NFPA 72, 18.
Temporal Code 3 is the standard audible notification in a modern system. Voice Evacuation is the second most common audible in a modern system. Legacy systems, typically found in older schools and building have used continuous tones alongside other audible schema. High-reliability speakers are used to notify the occupants of the need for action in connection with a fire or other emergency. These speakers are employed in large facilities where general undirected evacuation is considered impracticable or undesirable.
The signals from the speakers are used to direct the occupant’s response. The system may be controlled from one or more locations within the building known as Fire Wardens Stations, or from a single location designated as the building Fire Command Center. Speakers are automatically actuated by the fire alarm system in a fire event, and following a pre-alert tone, selected groups of speakers may transmit one or more prerecorded messages directing the occupants to safety. These messages may be repeated in one or more languages. Trained personnel activating and speaking into a dedicated microphone can suppress the replay of automated messages in order to initiate or relay real-time voice instructions. 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. Voice-based systems provide response personnel with the ability to conduct orderly evacuation and notify building occupants of changing event circumstances.