DEFINITIONS


Address
A binary/hexadecimal/decimal number that uniquely identifies a specifies device, module or power supply.
Addressable module
An addressable device which act as a transponder for one or more smoke detector, manual station or other conventional alarm devices so that an area may be identified by activation of one device connected to the addressable zone module.
Addressable Device
A fire alarm system component with discreet identification that can have its status individually identified, or that is used to individually control other functions.
Alarm Verification
A feature of some automatic fire detection and alarm systems to reduce unwanted alarms. Detectors must report alarm conditions for a minimum period of time, or confirm alarm conditions within a given time period after being reset, to be accepted as a valid alarm initiating signal.
Analog Signal An electrical signal that varies continuously in amplitude or frequency with the information being transmitted.
Automatic Fire Detectors
A device designed to detect the presence of fire or the products of combustion. Including but not limited to heat detectors, flame detectors, smoke detectors.
Analog Initiating Device
 An initiating device that transmits a signal indicating varying degrees of condition, such as smoke obscuration levels. As contrasted with a conventional initiating device which can only indicate an “on/off” condition
Annunciator
A unit containing two or more indicator lamps, alphanumeric displays, or other equivalent means in which each indication provides status information about a circuit, condition, or location. A visual and/ or audible device that indicate an alarm or another condition. Annunciator typically located at building entrance or at emergency control location to provide a clear indication of zone or device using standard LEDs and often include a customized graphic representation of building layout for speed response. Annunciator may incorporator features such as system common controls, auxiliary fan and damper control and paging control.
Alarm Signal
A signal indicating an emergency requires immediate action, such as a signal indicative of a fire or gas leak.

Acknowledge

A deliberate action of the panel operator to confirm that a message or event indicator has been seen.  This function, also abbreviated to "ACK", is used to acknowledge an abnormal situation such as an alarm, trouble or supervisory. The acknowledge function tells the panel that building personnel or emergency responders are aware of the alarm, trouble, or supervisory condition. Acknowledging the alarm or trouble condition also normally silences the panel's own sounder, but does not silence any Notification Appliances.
Air Sampling Type Detector
A detector that consists of a piping or tubing distribution network from the detector to the areas being protected. A fan in the detector housing draws air from the protected area back to the detector. The air is analyzed for
Products of combustion
All Clear
An audible signal used to communicate a “safe to return” condition to people already evacuated from a building
Automatic Extinguishing System Operation Detector A device that detects the operation of an extinguishing system by means
appropriate to the system employed. Including but not limited to water flow devices.
Automatic Extinguishing System Supervision
Devices that respond to abnormal conditions that could affect the proper
operation of an automatic sprinkler system or other fire extinguishing system. Including but not limited to control valves, pressure
levels, room temperature, etc.
Automatic Fire Detectors
A device designed to detect the presence of fire or the products of combustion. Including but not limited to heat detectors, flame detectors, smoke detectors.
Auxiliary Fire Alarm System
A system connected to a municipal fire alarm system for transmitting an alarm of fire to the public fire service communication center. Fire alarms from an auxiliary system are received at the public fire service communication center
on the same equipment and by the same methods as alarms transmitted manually from municipal fire alarm boxes located on streets.
Baud Rate
The measure of the speed of transmission of a digital signal
Block Diagram
A drawing showing the major control and annunciation components of a life safety system, their location, and the connecting wire wet been them
 Building Management System ( Bms)
An integrated computer system for monitoring and controlling various aspects of buildings operation including heating lighting Air conditioning etc.
Bus
A wire channel or path for transferring data or electrical signals e.g. data bus Audio signal bus, signal bus
Channel
A data communication line or audio pre-amp output that is dedicated to a specific function, such as paging or evacuation signaling
CLASS-A Wiring
In class A wiring, 2 wires start from fire alarm control panel terminal, makes connection with all field devices and the same 2 wires run back into the fire alarm control panel from end device connected in the circuit. Total 4 wires connected in the fire alarm panel terminals.  In this type of wiring a wire that broke or came loose would cause a TROUBLE condition but all devices would continue to be available to detect an alarm.
Class B wiring
In class B wiring, 2 wires start from fire alarm control panel terminal, makes connection with all detectors and then terminate at end of line resistor for monitor the loop. ". If a wire broke or came loose a trouble signal would occur, but all devices after the break point would not function.
Central Station Fire Alarm System
A system or group of systems in which the operations of circuits and devices are
transmitted automatically to, recorded in, maintained by, and supervised from a listed central station.
 Cross zone
An alarm detection and processing method in which a logical AND operation is programmed  wet been two initiating device zones, so that operation of one of the zones will cause an alert signal, For example , an operation of the second zone  will cause an evacuation signal and/or specific auxiliary device activation.
Combination Detector
 A device that either responds to more than one fire phenomenon or employees more than one operating principle to sense one of these phenomenons. Typical examples are combination smoke/heat detectors or a combination rate of rise and fixed temperature heat detector
Display
The visual representation of output data other than printed copy.
Detector Coverage
A recommended maximum distance between adjacent detectors or that area that a detector is designated to protect.
Digital Signal
A signal that represents just two voltage levels is a digital signal. A digital signal has only two states. The signal is not continuously variable. The two states can be expressed in various ways. High/Low, ON/OFF, 0/1.
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.
DIP Switch
A two positioning electrical switch used to program hardware to specific software address or functions.
Disable
A command which prevent an input device /circuit zone from reporting its change of state or an output device/circuits/zone from changing state.
Evacuation
 The withdrawal of occupants from a building.
End of Line Device (EOL)
A device such as a resistor or diode placed at the end of a class B circuit to maintain supervision
 Exit Plan
 Plan for the emergency evacuation of the premises.
End of line resistor
A resistor installed at the end of device wiring loop to establish a supervision current back to the panel or control unit.
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.
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
Fiber Optics
 A glass fiber medium that utilize light transmission to achieve extremely fast, secure and noise immune communications over long distance. Other advantages no cross talk, wide bandwidth, lightening and power surge immunity, and it suitable for explosive environment applications.
Fire detector
A device which detect a fire signature and automatically initiate an electrical signal to actuate an alert or alarm signal
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 re settable power for the detector and the second circuit monitors the contact on the device. These types of devices are not listed for compatibility
 Full Duplex
A communication circuit that allows simultaneous transmission data in two directions
Ground Fault
A circuit resistance to ground resulting from an abnormal condition that causes a control panel trouble condition.
Heat Detector
A device that detects abnormally high temperature or rate of temperature rise.
Heat Detector non Restorable
A device whose sensing element will be destroyed by the process of detecting a fire.
Heat Detector Restorable
A device whose sensing element not destroyed by the process of detecting a fire. Restoration may be automatic or manually.
Heat Detector Rate of Rise
A device that will respond when the temperature rises in excess of a predetermined rate.
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
 Input
Provide information about operating conditions (switches sensors)
Latching
Locked on. A latching device will remain Active until reset.
 Light Scattering Smoke Detector
 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.
Log
Record or history of the operation of the processing equipment, listening each event’s occurrence, time action, etc.
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.
Proprietary Fire Alarm System
An installation of fire alarm systems that serve contiguous and non contiguous properties underone ownership from a proprietary supervising station located at the protected property.
Manual Alarm Station [Pull Station]
A manually operated device used to initiate an alarm signal.
Module
A plug in circuit board, dedicated to a specific system function such as input signal receiving Circuit, auxiliary relay control, tone signal generation.
Monitor Input
A system input that is generally connected to a contact device that follows the operation of auxiliary devices such as damper or automatic doors.
Morse Code
A communication code that translates letters and numbers into combinations of long and short pulses.
Notification Appliance Circuit (NAC)
A circuit directly connected to a notification appliance.
National Fire Protection Association [NFPA]
Administers the development of and publishes codes, standards, and other Materials concerning all phases of fire safety.
Nationally Recognized Testing Laboratory (NRTL)
a laboratory that is recognized by the Occupational Safety and Health
Administration as meeting the necessary qualifications specified in the Code of Federal Regulations. Common NRTL in the United
States that deal with fire alarm products are FM Approvals, Intertek Testing Services (ETL) and Underwriters Laboratories Inc. (ULI)
Non restorable Initiating Device
A device whose sensing element is designed to be destroyed in the process of operation.
Notification Appliance
A fire alarm system component such as a bell, horn, speaker, strobe, etc. that provides an audible or visible output or both.
Obscuration
 A reduction in the atmospheric transparency caused by smoke. Usually  expressed in percent per foot.
Out Put
Causes an electrical or electronic device to operate (lamps LED’s, Relays, motors)
Photoelectric Smoke Detector
 A smoke detector utilizing a light source and a photosensitive sensor so arranged that the rays from the light do not normally shine on the photosensitive sensor. When smoke enters the light path, some of the light reflects off the smoke onto the sensor, causing the detector to respond.
Polarized Signaling Device
A signaling device that only operates if the correct electric polarity is established across the signal circuit by the control panel.
Restorable Initiating Device
A device whose sensing element is not ordinarily destroyed in the process of operation.
Restoration may be manual or automatic.
Remote Station Fire Alarm System
 A system installed in accordance with NFPA 72 to transmit alarm, trouble and supervisory
from one or more protected premises to a remote location at which appropriate action is taken.
RF( radio frequency)
Electromagnetic radiation, generally above 20 kHz, that may cause unwanted noise in communications wiring.
Redundant Wiring Circuit (or alternate path circuit)
The circuit has two continuous path, separately protected, connecting all components on the circuit.
Reset
A reset common control function that attempt to return the alarm system or device to its normal operation condition. Cancelling all programming until the reset is completed and new input status information can be processed. All input device and circuit must be in their normal state before the system will reset completely.
Reversing Polarity
 The electric characteristic of an equipment module that define a switching from a normal to an active state by the revising of the line polarity
Security Circuit
A dedicated circuit or device used to monitoring secure areas, doors or windows for accessing and intrusion violations.
Signaling Line Circuit: A circuit or path between any combination of circuit interfaces, control units, or transmitters over which
multiple system input signals or output signals, or both are carried.

Signal Silence
Also known as alarm silence or audible silence. Depending on the configuration of the alarm system, this function will either silence the system's notification appliances completely, or will silence only the audible alarm, with strobe lights continuing to flash. Audible silence allows for easier communication amongst emergency responders while responding to an alarm. This can also be used during construction as a means of a preliminary test, before the final full test.

Spot Type Detector
A device whose detecting element is concentrated at a particular location. Examples include certain smoke
and heat detectors.
Stratification An effect that occurs when air containing smoke particles or products of combustion is heated by burning material,
rises until it reaches a level where there is no longer a temperature difference between it and the surrounding air
Supervisory Signal
A signal indicating an “off normal” condition on the fire suppression system. Examples include, tamper indication, low air pressure and low building temperature
Thermal Lag
 The difference between the operating temperature of a thermal detector and the actual air temperature.
Two-Wire Smoke Detector
A smoke detector that initiates an alarm condition on the same pair of wires that supply power to the detector.
Walk test
Walk test allows the functional testing of the system's devices without the assistance of additional people at the control panel itself. It is also designed to allow initiating devices to be tested without setting off the building's alarms. Most panels offer the option for a silent walk test (no alarms activate) or an audible walk test (alarms activate for a brief period when a device is initiated). A system trouble is typically generated while the panel is in walk test mode. On European panels, this is usually an engineer-only function & cannot be activated by a user.

Zones

Zones are usually made by dividing a building, or area into different sections. Then depending on the specific zone, a certain amount and type of device is added to the zone to perform its given job.

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