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Intro to Basic Fire Alarm Technology

Intro to Basic Fire Alarm Technology. Silent Knight :: 7550 Meridian Circle :: Maple Grove, MN 55369 :: 800-328-0103. Basic Fire. Let’s examine the components that make a basic Fire Alarm Control System. Main Controller. The brains of the system

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Intro to Basic Fire Alarm Technology

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  1. Intro to Basic Fire AlarmTechnology Silent Knight :: 7550 Meridian Circle :: Maple Grove, MN 55369 :: 800-328-0103

  2. Basic Fire Let’s examine the components that make a basic Fire Alarm Control System.

  3. Main Controller • The brains of the system • Provides power to the system, monitors inputs and controls outputs through various circuits • Performs other functions as required by the appropriate code

  4. Primary (AC) Secondary (DC) Elements of a Control Panel Requires two Power Sources

  5. Elements of a Control Panel Inputs A fire alarm system can have a variety of input devices. Smoke Detector Manual Pull Station

  6. Inputs • Initiating Device: A system component that originates transmission of a change of state condition, such as a smoke detector, manual fire alarm box, supervisory switch, etc... • Initiating Device Circuit (IDC): A circuit to which automatic or manual initiating devices are connected where the signal received does not identify the individual device operated

  7. Elements of a Control Panel Outputs Horns Strobes

  8. Outputs • Notification Appliance: A fire alarm system component such as a bell, horn, speaker, light, or text display that provides audible, tactile, or visible output, or any combination thereof. • Notification Appliance Circuit: A circuit or path directly connected to a notification appliance.

  9. Primary (AC) The Basic System Main Controller Inputs Outputs Secondary (DC)

  10. Basic Fire Alarm Technology • Signal Initiation/Initiating Devices • Need to understand stages of fire and what technology works best for each

  11. The Stages of a Fire • Stage One • Incipient: Products of Combustion particles are produced (<0.3 microns). No visible smoke or detectable heat. May occur for milliseconds or days. • Use ionization detectors

  12. The Stages of a Fire • Stage Two • Smoldering: Visible smoke particles are produced (>0.3 microns). Little visible flame or noticeable heat. • Use Photoelectric Detectors

  13. The Stages of a Fire • Stage Three • Flame: Rapid combustion produces radiant energy in the visible, and invisible (IR, UV) spectrums. Heat begins to buildup at this stage • Use Spark or Flame Detectors

  14. The Stages of a Fire • Stage Four • High Heat: Uncontrolled combustion is caused by the heating of nearby combustibles to their ignition point. • Use Heat Detectors • Note! Major disadvantages of using thermal energy for fire identification are • Takes a while for a fire to be recognized • The toxic gases that are produced before an alarm point is reached

  15. Types of Detectors • Photoelectric • Light Scattering • Light Obscuration • Ionization • Duct • Heat (Thermal)

  16. Photoelectric Smoke Detectors:Light-Scattering Type • Uses a Light-Emitting Diode (LED) that sends a beam of light into a dark chamber- a photo diode sits on the other side of a partition within the chamber   • Smoke particles entering the chamber deflect some of the light rays into the photo cell. The photo cell generates a current when exposed to light, and if the current reaches a certain level, the detector alarms.

  17. Photoelectric Smoke Detectors:Light Obscuration Type • In a projected Beam Detector, alarms are generated by diffusing the projected light beam by a specified percentage of obscuration. • Total beam blockage generally results in a trouble signal.

  18. Ionization Smoke Detectors • Contain a small amount of radioactive material encapsulated in a metal chamber. Ionizing radiation develops a low, but steady electrical current.  Smoke particles entering the chamber disrupt the current and trigger the detector's alarm.  • Ion detectors react more quickly to fast flaming fires that give off little smoke.

  19. Heat Detectors • Fixed Detectors: • Alarm when the sensing element reaches a certain set point. • Two common models have 135 and 200-degrees F range. • Fixed element is generally a non-restorable type, and when activated, must be replaced. • Rate-of-Rise Detectors: • Respond when the rate of temperature increase is greater than an allowable limit (15 degrees in 60 secs.) (placement in a stable environment) (e.g.. ovens, heating vents, etc.). • The Rate-of-Rise element is restorable when conditions return to normal. • Rate Compensation will respond regardless of the rate of temperature rise.

  20. Duct Detectors • Photoelectric detector mounted in housing outside the ductwork that has probes that extend into the duct to sample the air inside the duct. • Primarily used as a smoke control device to control the flow of air in ductwork.

  21. Initiating DevicesManual Fire Alarm Stations • Manually-operated device used to initiate an alarm signal • Single Action Stations require a single operation to activate it. Generally a pulling down action. • Dual Action Stations require two distinct operations. A set-up and an activating action.

  22. Notification Appliances Types • Audible - Horns, Bells, Sounders, Sirens, Chimes, Speakers • Visual - Strobes • Physical - Bed shakers • Olfactory - Smell

  23. Audible Devices • Bells: Used if they are only for fire, or have a distinctive sound from other bell signaling devices. Often used as an external gong to indicate the flow of water in the sprinkler system. • Horns: Loud and distinctive output. Often used in high-noise environments, such as manufacturing plants.

  24. Audible Devices • Sounders: Electronic or mechanical audible devices, which are capable of producing a variety of tones. Often, the tone is selectable during installation of the device. • Chimes: Soft-toned appliances used where loud noises could be disruptive to other operations. Generally used where qualified personnel are continuously in attendance.

  25. Audible Devices • Sirens: Extremely loud devices generally limited in use to outdoor or heavy industrial areas. • Speakers: Audible devices used in conjunction with voice evacuation messages. Life-Safety speakers are not generally associated with Muzak systems.

  26. Visual Signaling Appliances Visual signaling appliances are used in high-noise environments, in areas occupied by hearing-impaired individuals, or in areas where audible devices may not be desired.

  27. Speaker/Strobe Visual Devices Strobe Chime/Strobe Horn/Strobe

  28. The Fire Alarm Systems

  29. Types of Fire Alarm Control Panels • Conventional (hard wired) • Fixed • Programmable • Addressable (multiplexed) • Intelligent (analog data transfer)

  30. Conventional “Hard Wired” System • Simplest type of control unit. • Generally, a single circuit board contains power supply, control, initiating and notification circuitry. • Some models use auxiliary circuit boards to perform special functions. • Input/output devices connect to dedicated circuits. • Designated outputs occur when initiating signals are received. • Limited special functions and capabilities.

  31. Conventional “Programmable” System • Basic “Designed System” • Components selected by the designer to meet the direct needs of the customer. • Initiating circuits are programmable for fire, waterflow, supervisory service, etc. • Output circuits are programmable for code selection and silenceability. • On some systems, input-to-output CIRCUIT (not device) mapping.

  32. Addressable System • Each device (detector, pull station…) has a unique number assigned to it called the address for reporting alarms and troubles. • Employs a Signaling Line Circuit (SLC) Loop along which all addressable input and output devices are connected to the fire alarm control panel. • Addressable devices transmit an electronic message back to the Control Unit representing their state (Normal, Alarm, Trouble) when polled by the Control Unit.

  33. Analog System • Always an Addressable System. • Processes detailed, analog data from detectors about smoke levels. • Can provide sensitivity data for each detector. • Employs Drift Compensation (self calibration) in its detectors.

  34. Terminology • FACP - Fire Alarm Control Panel. • FACU - Fire Alarm Control Unit. • FCC - Federal Communications Commission • UL - Underwriters Laboratories • NFPA - National Fire Protection Agency. • AHJ, LAHJ - Authority Having Jurisdiction, Local AHJ • ADAAG - Americans with Disabilities Act Accessibility Guidelines. • PoC - Products of Combustion • LED - Light Emitting Diode • IDC - Initiating Device Circuit • NAC - Notification Appliance Circuit • ELR, EOL - End of Line Resistor

  35. Terminology • NEC - National Electrical Code (NFPA 70) • NEMA - National Electrical Manufacturing Association • EIA - Electronics Industry Association • Cd - Candela • dB, dBA - Decibels • FWR - Full Wave Rectified • ANSI - American National Standards Institute • PIV - Post Indicator Valve • OS&Y - Outside Stem and Yoke Valves • SFPE - Society for Fire Protection Engineers • Shall - Indicates a mandatory requirement • Should - Indicates a recommendation or advisement

  36. References • NFPA 70 - National Electrical Code • NFPA 72 - National Fire Alarm Code • NFPA 101 - Life Safety Code • National Electrical Code Handbook, NFPA • Life Safety Code Handbook, NFPA • Fire Protection Handbook, NFPA • Fire Alarm Signaling Systems, NFPA

  37. Basic Fire Alarm Technology Please visit www.farenhyt.com for fire alarm system solutions for your facility Silent Knight :: 7550 Meridian Circle :: Maple Grove, MN 55369 :: 800-328-0103

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