Fire and Emergency Alarm System
Part I- Basics
This module will describe:
1. Components and the arrangements of components in fire and emergency alarm systems.
2. How these systems work.
Power Supply
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A source of electrical operating power, including the circuits and terminations connecting it to the dependent systemcomponents.
•
In alarm systems there much be two supplies of power (primary and secondary)•
NFPA Standards•
72: National Fire Alarm and Signaling CodeControl Unit
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A system component that monitors inputs and controls outputs through various types of circuits.•
NFPA StandardsAlarm Initiating Devices
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A system component that originates transmission of a change-of-state condition, such as in a smoke detector, manual fire alarm box, or supervisory switch.•
Can be manual or automatic•
NFPA StandardsAlarm Initiating Devices:
Manual Pull Stations
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Manual•
Red in colorAlarm Initiating Devices:
Smoke Detectors
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Automatic•
A listed device that senses visible or invisible particles of combustion•
Two main types•
ionization•
photoelectricAlarm Initiating Devices:
Heat Detectors
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Automatic•
Initiates an alarm when the thermal energy of a fireincreases the temperature of a heat sensitive element.
•
Two main types•
Rate-of-riseAlarm Initiating Devices:
Radiant Energy Detectors
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Automatic•
Responds to the radiant energy that has traveled from the fire to the detector•
Two main types•
Flame detectorAlarm Initiating Devices:
Gas Detectors
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Automatic•
Detects the presence of various gases•
Two main types•
Fixed•
PortableAlarm Initiating Devices:
Combination Detectors
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A device that:•
responds to more than one of the fire phenomena; or•
employs more than one operating principle to sense one of these phenomena.•
Examples:•
Heat detector with a smoke detectorAlarm Initiating Devices:
Sprinkler Water Flow Switches
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Automatic•
Initiates an alarm signal when the flow of water through the wetpipe sprinkler system is greater than that going through one sprinkler head
Alarm Notification Appliances
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A fire alarm system component such as a bell, horn, speaker, light or text display that providesaudible, tactile or visible outputs, or any combination thereof.
•
The primary purpose is to convey information to building occupants during a fire emergency•
NFPA Standards•
72: National Fire Alarm andAlarm Notification Appliances: Audible
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Horns & Speakers•
Must be audible and intelligibleAlarm Notification Appliances:
Visible
•
Strobe lights or illumination•
Must be accessible and visibleSupervision
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A visual and audible alarm signal given at the central safety station to indicate when the system is in operation or when a condition that would impair the satisfactory operation of the system exists.•
NFPA•
13: Standard for the Installation of Sprinkler SystemsSupervision: Protected Premises
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Protected premises are all buildings, structures, facilities, real property, or portions thereof protected by an alarm system.•
A protected premises alarm system is designed to:•
Warn building occupants to evacuate the premise•
Actuate the building’s fire-protection featuresSupervision: Supervising Station
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A facility that receives signals and at which personnel are in attendance at all times to respond to these signals•
Three types•
Remote supervising-station fire alarm systems•
Propriety supervising-station systemsSupervision: Remote Station
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A supervising station:•
to which alarm, supervisory, or trouble signals or any combination of those signals emanating from protected premises fire alarm systems are received•
where personnel are in attendance at all times to respond.Supervision: Propriety Supervising Station
•
A supervising station:•
under the same ownership as the protected premises fire alarm system(s) that it supervises•
to which alarm, supervisory, or trouble signals are received•
where personnel are in attendance at all times to supervise operation and investigate signals.Supervision: Central Station
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A supervising station:•
that is listed for central station service•
that commonly provides lessstringent supervising station services such as remote supervising station services.
•
It is where•
the monitoring of the system and signals occurs•
retransmission of signals to the appropriate emergency-response service and record keeping will occurSupervision: Digital Alarm Communicator Transmitter
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Transmit an alarm signal from the property to the centralsupervising station.
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Is connected to the public-switched telephone network upstream of any telephone system on the property.Single-Station Smoke Alarms
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A detector comprising an assembly that incorporates a sensor, control components, and an alarmnotification appliance in one unit operated from a power source either located in the unit or
obtained at the point of installation.
•
NFPA Standards•
72: National Fire Alarm andMultiple-Station Smoke Alarms
•
Two or more single station alarm devices that can beinterconnected so that actuation of one causes all integral or separate audible alarms to operate; or one single station alarm device having connections to other detectors or to a manual fire alarm box.
