Potter Fire Alarm Systems - Manual (Page 6)

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Fire Alarm Training • 8700055 • Rev F • 4/10
Compatibility Listed: A specific listing process that applies only to two wire devices [such as smoke detectors] designed to
operate with certain control equipment.
Digital Alarm Communicator Receiver [DACR]: A system component that will accept and display signals from digital alarm
communicator transmitters [DACT] sent over public switched telephone network.
Digital Alarm Communicator System [DACS]: A system in which signals are transmitted from a digital alarm communicator
transmitter [DACT] located at the protected premises through the public switched telephone network to a DACR.
Digital Alarm Communicator Transmitter [DACT]: A system component at the protected premises to which initiating devices
are connected. The DACT will seize the connected telephone line, dial a pre-selected telephone number to connect to a DACR,
and transmit signals indicating a status change of the initiating device.
Display: The visual representation of output data other than printed copy.
Evacuation: The withdrawal of occupants from a building.
Note: Evacuation does not include relocation of occupants within a building.
End Of Line Device: A device such as a resistor or diode placed at the end of a class B circuit to maintain supervision.
End Of Line Relay: A device used to supervise power [usually for 4-wire smoke detectors] and installed within or near the last
device on an initiating circuit.
Evacuation Signal: Distinctive signal intended to be recognized by the occupants as requiring evacuation of the building.
Exit Plan: Plan for the emergency evacuation of the premises.
Fire Alarm Control Unit [Panel]: A system component that receives inputs from automatic and manual fire alarm devices and
may supply power to detection devices and transponders or
off-premises transmitters. The control unit may also provide transfer of power to the notification appliances and transfer condition
of relays or devices connected to the control unit. The fire alarm control unit can be a local unit or a master control unit.
Fire Rating: The classifications indicating in time [hours] the ability of a structure or component to withstand fire conditions.
Fire Safety Functions: Building and fire control functions that are intended to increase the level of life safety for occupants or to
control the spread of harmful effects of fire.
Flame Detector: A device that detects the infrared, ultraviolet, or visible radiation caused by fire.
Four Wire Smoke Detector: a smoke detector that has two distinct circuits used in its operation. The first circuit provides
resettable power for the detector and the second circuit monitors the contact on the device. These types of devices are not listed
for compatibility.
Heat Detector: A device that detects abnormally high temperature or rate of temperature rise.
Initiating Device: A system component that originates transmission of a change of state condition, such as a smoke detector,
water flow switch, etc.
Initiating Device Circuit: A circuit to which automatic or manual initiating devices are connected.
Ionization Smoke Detector: A smoke detector that has a small amount of radioactive material which ionizes the air in the
sensing chamber, thus rendering it conductive and permitting a current to flow between two charged electrodes. This gives
the sensing chamber an effective electrical conductance. When smoke particles enter the sensing chamber they decrease the
conductance of the air by attaching themselves to the ions, causing a reduction in mobility. When conductance is reduced to less
than a predetermined level, the detector responds.
Level Ceilings: Those ceilings that are actually level or have a slope of less than 1 1/2 in. per foot.
Light Scattering: The action of light being reflected and/or refracted off particles of combustion for detection by a photoelectric smoke detector.
Line Type Detector: A device in which detection is continuous along a path. Examples include projected beam smoke detectors
and heat sensitive cable.
Listed: Equipment or materials included in a list published by an organization acceptable to the “authority having jurisdiction” and
concerned with product evaluation, that maintains periodic inspection of production of listed equipment or materials and whose listing
states either that the equipment or material meets appropriate standards or has been tested and found suitable for use in a specific manner.
Note: The means for identifying listed equipment may vary for each organization concerned with product evaluation, some of
which do not recognize as listed unless it is also labeled. The “authority having jurisdiction” should utilize the system employed
by the listing organization to identify a listed product.
Local Fire Alarm System: A local system sounding an alarm at the protected premises as the result of the operation of automatic
or manual initiating devices.