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Intro to Intro to Basic Fire AlarmBasic Fire Alarm

TechnologyTechnology

Silent Knight :: 7550 Meridian Circle :: Maple Grove, MN 55369 :: 800-328-0103

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Basic FireBasic Fire

Let’s examine the Let’s examine the components that components that make a basic Fire make a basic Fire

Alarm Control Alarm Control System.System.

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Main ControllerMain Controller• The brains of the The brains of the

systemsystem• Provides power to Provides power to

the system, the system, monitors inputs monitors inputs and controls and controls outputs through outputs through various circuitsvarious circuits

• Performs other Performs other functions as functions as required by the required by the appropriate codeappropriate code

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Primary (AC)

Secondary (DC)

Requires two Power SourcesElements of a Control PanelElements of a Control Panel

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Smoke Detector

Manual Pull Station

A fire alarm system can have a variety of input devices.

InputsElements of a Control PanelElements of a Control Panel

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InputsInputs• Initiating Device: A system Initiating Device: A system

component that originates component that originates transmission of a change of state transmission of a change of state condition, such as a smoke detector, condition, such as a smoke detector, manual fire alarm box, supervisory manual fire alarm box, supervisory switch, etc...switch, etc...

• Initiating Device Circuit (IDC): A circuit Initiating Device Circuit (IDC): A circuit to which automatic or manual to which automatic or manual initiating devices are connected initiating devices are connected where the signal received does not where the signal received does not identify the individual device operatedidentify the individual device operated

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Elements of a Control PanelElements of a Control Panel

Horns

Strobes

Outputs

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OutputsOutputs• Notification Appliance: A fire Notification Appliance: A fire

alarm system component such as alarm system component such as a bell, horn, speaker, light, or a bell, horn, speaker, light, or text display that provides text display that provides audible, tactile, or visible output, audible, tactile, or visible output, or any combination thereof.or any combination thereof.

• Notification Appliance Circuit: A Notification Appliance Circuit: A circuit or path directly connected circuit or path directly connected to a notification appliance.to a notification appliance.

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The Basic SystemThe Basic System

Secondary (DC)

Primary (AC)

Outputs

Inputs

Main Controller

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Basic Fire Alarm TechnologyBasic Fire Alarm Technology• Signal Initiation/Initiating DevicesSignal Initiation/Initiating Devices

Need to understand stages of fire Need to understand stages of fire and what technology works best for and what technology works best for eacheach

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The Stages of a FireThe Stages of a Fire• Stage OneStage One

Incipient: Products of Combustion Incipient: Products of Combustion particles are produced (<0.3 particles are produced (<0.3 microns). No visible smoke or microns). No visible smoke or detectable heat. May occur for detectable heat. May occur for milliseconds or days. milliseconds or days. • Use ionization detectorsUse ionization detectors

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The Stages of a FireThe Stages of a Fire• Stage TwoStage Two

Smoldering: Visible smoke particles Smoldering: Visible smoke particles are produced (>0.3 microns). Little are produced (>0.3 microns). Little visible flame or noticeable heat. visible flame or noticeable heat. • Use Photoelectric DetectorsUse Photoelectric Detectors

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The Stages of a FireThe Stages of a Fire• Stage ThreeStage Three

Flame: Rapid combustion produces Flame: Rapid combustion produces radiant energy in the visible, and radiant energy in the visible, and invisible (IR, UV) spectrums. Heat invisible (IR, UV) spectrums. Heat begins to buildup at this stagebegins to buildup at this stage• Use Spark or Flame DetectorsUse Spark or Flame Detectors

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The Stages of a FireThe Stages of a Fire• Stage FourStage Four

High Heat: Uncontrolled combustion High Heat: Uncontrolled combustion is caused by the heating of nearby is caused by the heating of nearby combustibles to their ignition point. combustibles to their ignition point. • Use Heat DetectorsUse Heat Detectors

Note! Major disadvantages of using Note! Major disadvantages of using thermal energy for fire identification thermal energy for fire identification areare• Takes a while for a fire to be recognizedTakes a while for a fire to be recognized• The toxic gases that are produced The toxic gases that are produced

before an alarm point is reachedbefore an alarm point is reached

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Types of DetectorsTypes of Detectors• PhotoelectricPhotoelectric

Light ScatteringLight Scattering Light ObscurationLight Obscuration

• IonizationIonization• DuctDuct• Heat (Thermal)Heat (Thermal)

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Photoelectric Smoke Photoelectric Smoke Detectors:Detectors:

Light-Scattering TypeLight-Scattering Type• Uses a Light-Emitting Diode (LED) that Uses a Light-Emitting Diode (LED) that

sends a beam of light into a dark sends a beam of light into a dark chamber- a photo diode sits on the chamber- a photo diode sits on the other side of a partition within the other side of a partition within the chamber   chamber  

• Smoke particles entering the chamber Smoke particles entering the chamber deflect some of the light rays into the deflect some of the light rays into the photo cell. The photo cell generates a photo cell. The photo cell generates a current when exposed to light, and if current when exposed to light, and if the current reaches a certain level, the current reaches a certain level, the detector alarms.the detector alarms.

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Photoelectric Smoke Photoelectric Smoke Detectors:Detectors:

Light Obscuration TypeLight Obscuration Type• In a projected Beam In a projected Beam

Detector, alarms Detector, alarms are generated by are generated by diffusing the diffusing the projected light projected light beam by a specified beam by a specified percentage of percentage of obscuration.obscuration.

• Total beam Total beam blockage generally blockage generally results in a trouble results in a trouble signal.signal.

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Ionization Smoke DetectorsIonization Smoke Detectors• Contain a small amount of Contain a small amount of

radioactive material encapsulated radioactive material encapsulated in a metal chamber. Ionizing in a metal chamber. Ionizing radiation develops a low, but radiation develops a low, but steady electrical current.  Smoke steady electrical current.  Smoke particles entering the chamber particles entering the chamber disrupt the current and trigger the disrupt the current and trigger the detector's alarm. detector's alarm. 

• Ion detectors react more quickly Ion detectors react more quickly to fast flaming fires that give off to fast flaming fires that give off little smoke.little smoke.

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Heat DetectorsHeat Detectors• Fixed Detectors:Fixed Detectors:

Alarm when the sensing element reaches a certain Alarm when the sensing element reaches a certain set point. set point.

Two common models have 135 and 200-degrees F Two common models have 135 and 200-degrees F range.range.

Fixed element is generally a non-restorable type, and Fixed element is generally a non-restorable type, and when activated, must be replaced.when activated, must be replaced.

• Rate-of-Rise Detectors: Rate-of-Rise Detectors: Respond when the rate of temperature increase is Respond when the rate of temperature increase is

greater than an allowable limit (15 degrees in 60 greater than an allowable limit (15 degrees in 60 secs.) (placement in a stable environment) (e.g.. secs.) (placement in a stable environment) (e.g.. ovens, heating vents, etc.). ovens, heating vents, etc.).

The Rate-of-Rise element is restorable when The Rate-of-Rise element is restorable when conditions return to normal.conditions return to normal.

• Rate Compensation will respond regardless of Rate Compensation will respond regardless of the rate of temperature rise.the rate of temperature rise.

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Duct DetectorsDuct Detectors• Photoelectric Photoelectric

detector mounted detector mounted in housing outside in housing outside the ductwork that the ductwork that has probes that has probes that extend into the duct extend into the duct to sample the air to sample the air inside the duct.inside the duct.

• Primarily used as a Primarily used as a smoke control smoke control device to control device to control the flow of air in the flow of air in ductwork.ductwork.

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Initiating DevicesInitiating DevicesManual Fire Alarm StationsManual Fire Alarm Stations

• Manually-operated Manually-operated device used to device used to initiate an alarm initiate an alarm signalsignal Single Action Stations Single Action Stations

require a single require a single operation to activate operation to activate it. Generally a pulling it. Generally a pulling down action.down action.

Dual Action Stations Dual Action Stations require two distinct require two distinct operations. A set-up operations. A set-up and an activating and an activating action.action.

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Notification Appliances Notification Appliances TypesTypes

• Audible - Horns, Bells, Sounders, Audible - Horns, Bells, Sounders, Sirens, Chimes, SpeakersSirens, Chimes, Speakers

• Visual - StrobesVisual - Strobes• Physical - Bed shakersPhysical - Bed shakers• Olfactory - SmellOlfactory - Smell

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Audible DevicesAudible Devices• Bells: Used if they Bells: Used if they

are only for fire, or are only for fire, or have a distinctive have a distinctive sound from other sound from other bell signaling bell signaling devices. Often used devices. Often used as an external gong as an external gong to indicate the flow to indicate the flow of water in the of water in the sprinkler system.sprinkler system.

• Horns: Loud and Horns: Loud and distinctive output. distinctive output. Often used in high-Often used in high-noise environments, noise environments, such as such as manufacturing manufacturing plants.plants.

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Audible DevicesAudible Devices• Sounders: Electronic or Sounders: Electronic or

mechanical audible devices, mechanical audible devices, which are capable of which are capable of producing a variety of tones. producing a variety of tones. Often, the tone is selectable Often, the tone is selectable during installation of the during installation of the device.device.

• Chimes: Soft-toned appliances Chimes: Soft-toned appliances used where loud noises could used where loud noises could be disruptive to other be disruptive to other operations. Generally used operations. Generally used where qualified personnel are where qualified personnel are continuously in attendance.continuously in attendance.

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Audible DevicesAudible Devices• Sirens: Extremely Sirens: Extremely

loud devices loud devices generally limited in generally limited in use to outdoor or use to outdoor or heavy industrial heavy industrial areas.areas.

• Speakers: Audible Speakers: Audible devices used in devices used in conjunction with conjunction with voice evacuation voice evacuation messages. Life-Safety messages. Life-Safety speakers are not speakers are not generally associated generally associated with Muzak systems.with Muzak systems.

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Visual Signaling Visual Signaling AppliancesAppliances

Visual signaling appliances Visual signaling appliances are used in high-noise are used in high-noise environments, in areas environments, in areas

occupied by hearing-impaired occupied by hearing-impaired individuals, or in areas where individuals, or in areas where audible devices may not be audible devices may not be

desired.desired.

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Visual DevicesVisual Devices

Speaker/StrobeSpeaker/Strobe

Chime/Chime/StrobeStrobe

Horn/Horn/StrobStrob

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StrobeStrobe

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The Fire Alarm The Fire Alarm SystemsSystems

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Types of Fire Alarm Types of Fire Alarm Control PanelsControl Panels

• Conventional (hard wired)Conventional (hard wired) Fixed Fixed ProgrammableProgrammable

• Addressable (multiplexed)Addressable (multiplexed)• Intelligent (analog data transfer)Intelligent (analog data transfer)

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Conventional “Hard Wired” Conventional “Hard Wired” SystemSystem

• Simplest type of control unit.Simplest type of control unit.• Generally, a single circuit board contains Generally, a single circuit board contains

power supply, control, initiating and power supply, control, initiating and notification circuitry.notification circuitry.

• Some models use auxiliary circuit boards to Some models use auxiliary circuit boards to perform special functions.perform special functions.

• Input/output devices connect to dedicated Input/output devices connect to dedicated circuits.circuits.

• Designated outputs occur when initiating Designated outputs occur when initiating signals are received.signals are received.

• Limited special functions and capabilities.Limited special functions and capabilities.

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Conventional “Programmable” Conventional “Programmable” SystemSystem

• Basic “Designed System”Basic “Designed System”• Components selected by the designer to Components selected by the designer to

meet the direct needs of the customer.meet the direct needs of the customer.• Initiating circuits are programmable for Initiating circuits are programmable for

fire, waterflow, supervisory service, etc.fire, waterflow, supervisory service, etc.• Output circuits are programmable for Output circuits are programmable for

code selection and silenceability.code selection and silenceability.• On some systems, input-to-output On some systems, input-to-output

CIRCUIT (not device) mapping.CIRCUIT (not device) mapping.

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Addressable SystemAddressable System• Each device (detector, pull station…) has a Each device (detector, pull station…) has a

unique number assigned to it called the unique number assigned to it called the address for reporting alarms and troubles.address for reporting alarms and troubles.

• Employs a Signaling Line Circuit (SLC) Loop Employs a Signaling Line Circuit (SLC) Loop along which all addressable input and along which all addressable input and output devices are connected to the fire output devices are connected to the fire alarm control panel.alarm control panel.

• Addressable devices transmit an electronic Addressable devices transmit an electronic message back to the Control Unit message back to the Control Unit representing their state (Normal, Alarm, representing their state (Normal, Alarm, Trouble) when polled by the Control Unit.Trouble) when polled by the Control Unit.

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Analog SystemAnalog System• Always an Addressable System.Always an Addressable System.• Processes detailed, analog data Processes detailed, analog data

from detectors about smoke from detectors about smoke levels.levels.

• Can provide sensitivity data for Can provide sensitivity data for each detector.each detector.

• Employs Drift Compensation (self Employs Drift Compensation (self calibration) in its detectors.calibration) in its detectors.

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TerminologyTerminology• FACP - Fire Alarm Control Panel.FACP - Fire Alarm Control Panel.• FACU - Fire Alarm Control Unit.FACU - Fire Alarm Control Unit.• FCC - Federal Communications CommissionFCC - Federal Communications Commission• UL - Underwriters LaboratoriesUL - Underwriters Laboratories• NFPA - National Fire Protection Agency.NFPA - National Fire Protection Agency.• AHJ, LAHJ - Authority Having Jurisdiction, Local AHJAHJ, LAHJ - Authority Having Jurisdiction, Local AHJ• ADAAG - Americans with Disabilities Act Accessibility ADAAG - Americans with Disabilities Act Accessibility

Guidelines.Guidelines.• PoC - Products of CombustionPoC - Products of Combustion• LED - Light Emitting DiodeLED - Light Emitting Diode• IDC - Initiating Device CircuitIDC - Initiating Device Circuit• NAC - Notification Appliance CircuitNAC - Notification Appliance Circuit• ELR, EOL - End of Line ResistorELR, EOL - End of Line Resistor

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TerminologyTerminology• NEC - National Electrical Code (NFPA 70)NEC - National Electrical Code (NFPA 70)• NEMA - National Electrical Manufacturing AssociationNEMA - National Electrical Manufacturing Association• EIA - Electronics Industry AssociationEIA - Electronics Industry Association• Cd - CandelaCd - Candela• dB, dBA - DecibelsdB, dBA - Decibels• FWR - Full Wave RectifiedFWR - Full Wave Rectified• ANSI - American National Standards InstituteANSI - American National Standards Institute• PIV - Post Indicator ValvePIV - Post Indicator Valve• OS&Y - Outside Stem and Yoke ValvesOS&Y - Outside Stem and Yoke Valves• SFPE - Society for Fire Protection EngineersSFPE - Society for Fire Protection Engineers• Shall - Indicates a mandatory requirementShall - Indicates a mandatory requirement• Should - Indicates a recommendation or advisementShould - Indicates a recommendation or advisement

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ReferencesReferences• NFPA 70 - National Electrical CodeNFPA 70 - National Electrical Code• NFPA 72 - National Fire Alarm CodeNFPA 72 - National Fire Alarm Code• NFPA 101 - Life Safety CodeNFPA 101 - Life Safety Code• National Electrical Code Handbook, National Electrical Code Handbook,

NFPANFPA• Life Safety Code Handbook, NFPALife Safety Code Handbook, NFPA• Fire Protection Handbook, NFPAFire Protection Handbook, NFPA• Fire Alarm Signaling Systems, NFPAFire Alarm Signaling Systems, NFPA

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Silent Knight :: 7550 Meridian Circle :: Maple Grove, MN 55369 :: 800-328-0103