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Fire detection and alarm systems
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- 2. SUBMITTED TO: SUBMITTEDBY: AR. KIRANPREETKAUR PRAGYAA VASHISHTHA SURAJ VEER SINGH TRISHANJIT SINGH
- 3. FIRE • Fire isthe rapid oxidation of a material in the exothermic chemical process of combustion, releasing heat, light, and various reaction products. Slower oxidative processeslike rusting or digestion are not included by this definition • Fire in its most common form can result in conflagration, which has the potential to cause physical damage through burning. Fire is an important processthat affects ecological systems around the globe. The positive effects of fire include stimulating growth and maintaining various ecological systems.
- 4. HOW DOES FIRESPREAD? ONCE STARTED, A BUILDING FIRE IS LIKELY TO SPREAD UNTIL ALL FUEL HAS BEEN USED UP. THIS COULD HAVE DEVASTATING CONSEQUENCES FOR YOUR HOME OR BUSINE SS. BY UNDERSTANDING HOW FIRE SPREADS, YOU MAY BE BETTER EQUIPPED TO EX TINGUISH IT. • CHEMICALS AND COMBUSTIBLES: WHEN FIRE COMES IN CONTACT WITH LAB CHEMICALS, HOUSEHOLD CLEANERS, PAINT AND OTHER CHEMICALS, THE FIRE BURNS HO TTER AND MORE AGGRESSIVELY, ENCOURAGING IT TO SPREAD. OTHER COMBUSTIBLES COMMONLY FOUND IN THE HOME INCLUDE MATTRESSES, SOFA CUSHIONS, MAGAZINES, NEWSPAPERS AND VARIOUS TEXTILES. • OPEN SPACE: A BUILDING WITH LIMITED INTERIOR STRUCTURE BURNS MUCH FASTER T HAN ONE WITH HALLWAYS AND CLOSED DOORS. WALLS AND DOORS TRAP THE FIR E AND PREVENT THE FLAMES AND SMOKE FROM SPREADING. WHILE THE FIRE WILL EVENTUALLY BURN THROUGH THE STRUCTURE AND CONTINUE TO SPREAD IF LEFT TO ITS OWN DEVICES, A FIRE FIGHTING TEAM HAS A MUCH EASIER TIME DOUSING THE FLAMES I N A BUILDING WITH MORE WALLS AND DOORS, ESPECIALLY IF THOSE STRUCTURES ARE BU ILT TO WITHSTAND THE HEAT AND DAMAGE OF A FIRE.
- 5. • Construction materials:While a fire can burn through just about any modern building, fire resistive buildings made of concrete and steel curb the spread of fire better than wood frame homes. • Water: In some cases, water is not the best fire extinguisher. Grease fires, for example, can actuallyspread faster when doused with water. A special fire extinguisher or baking soda should be used to suffocate and stop the spread of grease fires in the kitchen.
- 6. CAUSES OF FIRE KitchenStoves: •Neverleavethestoveunattended. • Checkthatelectriccords, curtains,teatowelsand ovencloths are at a safe distance from thestovetop. • Becareful of long flowing sleevescontactinggas flames. Electric Blankets: • Do not sleepwith electricblanketson or leavethehousewithoutswitchingthemoff. • Neverleaveweightyobjects on thebed whentheelectricblanketis on. • Haveyour blanketcheckedby anauthorisedrepairerif yoususpectoverheating. • Alwaysfollow manufacturer´sinstructionsfor care and storage. • Inspecteach blanketfor wearand tearat thebeginningof thecooler months.
- 7. Faulty Wiring: • Alwaysusea qualified electrician. • Double adaptors and power-boards can overload power points. • Install safety switches and correctfuses. Smoking in Bed: • Smoking in bed can befatal -tinyembers can smoulder unnoticedand burst into flame muchlater. Lighting: • Checklight fittings for heat build up. • Discard lampshades that are close to light globes &lamp bases that can be knockedover easily. • Ensurerecessed downlights areproperly insulated from wood panelling or ceiling timbers. Flammable Liquids: • Store all flammable liquids such as petrol, kerosene, methylated spirits away from heat. • Always checkthe label before use and storage. • Useextreme carewhen pouring.
- 8. Clothes Dryers: • Alwayscleanlintfiltersaftereach load. • Avoid dryingbrasin yourdryerasthe underwirecanget caughtandstarta fire. Candles: • Neverleave burning candlesunattended.Donotsleep withaburningcandle. • Makesurecurtainsandotherflammableitems arewell awayfromburning candles. Home Heating: • Make sureall appliancesareprofessionallyinstalled. • Check thatwallsandfloorsareinsulatedfromheatsources. • Becarefulwhereyouplaceportableappliances. • Placeamesh guardin frontofopen fires. Children: • Warnall children aboutplayingwithfire. • Keep allmatches, lightersandcandlesoutofreachof small children. • Teachyoungchildren tobring matchesorlighters theyfindtoanadultimmediately. • Teacholderchildren thatmatchesarea tooltobeusedin thepresence ofadults.
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- 10. Detection • Fire detectorssenseone or more of the products or phenomena resulting from fire, such as smoke heat, infrared and/or ultraviolet light radiation, or gas. • In dwellings, smoke detectors are often stand-alonedevices. In non-domestic buildings, fire detection will typically takethe form of a fire alarm system, incorporating one or more of the following automatic devices Fire
- 11. Devices • Heat detector •Smoke detector • Flame detector • Fire gas detector
- 12. Heat detector • A'heatdetector is a fire alarm device designed to respond when the convicted thermal energy of a fire increases the temperature of a heat sensitive element. The thermal mass and conductivity of the element regulate the rate flow of heat into the element. • All heat detectors have this thermal lag. Heat detectors have two main classificationsof operation, "rate-of-rise" and "fixed temperature." The Heat detector is used to help in the reduction of damaged property. It is triggered when temperature increases.
- 13. Fixed temperature heatdetectors • Thisisthemostcommontypeofheatdetector.Fixedtemperaturedetectorsoperatewhentheheat sensitiveeutecticalloyreachestheeutecticpointchangingstatefroma solidtoa liquid. • Thermallagdelaystheaccumulationofheatat thesensitiveelementsothata fixed-temperaturedevice willreachitsoperatingtemperaturesometimeafter thesurroundingair temperatureexceedsthat temperature. • Themostcommonfixedtemperature pointforelectricallyconnectedheatdetectorsis 136°F(58°C). Technologicaldevelopmentshaveenabledtheperfectionofdetectorsthatactivateata temperature of 117°F(47°C),increasingtheavailablereactiontime andmarginofsafety.
- 14. Rate-of-rise heat detectors •Rate-of-Rise (ROR) heat detectors operate on a rapid rise in elementtemperature of12° to15°F (6.7°to8.3°C) increase per minute, irrespective of the starting temperature. This type of heat detector can operate at a lower temperature fire condition than would bepossible if the threshold were fixed. • It has two heat-sensitive thermocouples orthermistors. Onethermocouple monitors heat transferred by convection or radiation. Theotherresponds to ambient temperature. Detectorresponds when first’s temperature increases relative to the other. • Rate of risedetectors may not respond to low energyrelease rates of slowly developing fires. To detect slowly developing fires combination detectors add a fixed temperature element that will ultimately respond when the fixed temperature element reaches the design threshold.
- 15. Rateof rise detector Fixedtemperature detector
- 16. Smoke detector • Asmokedetector is a device that senses smoke, typically as an indicator of fire. Commercial security devices issue a signal to a fire alarm control panel as part of a fire alarm system,while household smoke detectors, also known as smoke alarms, generally issue a local audible orvisual alarm from the detector itself.
- 17. Working of smokedetector
- 18. Types of smokedetectors • Ionization smokedetector • Photoelectric, or optical, smoke detector • Carbon monoxide and carbon dioxide detection
- 19. Ionization smoke detector •An ionization smoke detector uses a radioisotope, typically americium-241, toionize air; a difference dueto smoke is detected and an alarmis generated. Ionization detectors are moresensitive to the flaming stage of fires than optical detectors, while optical detectors are moresensitive to fires in the early smoldering stage.
- 20. Photoelectric, or optical,smoke detector • Aphotoelectric,oroptical,smokedetectorcontainsa sourceofinfrared,visible,or ultravioletlight (typicallyanincandescentlightbulborlight-emittingdiode),a lens,anda photoelectricreceiver(typically aphotodiode). • Inspot-typedetectorsallofthesecomponentsare arrangedinsidea chamberwhereair,whichmay containsmokefroma nearbyfire,flows. • Inlarge openareassuchas atriaandauditoriums,opticalbeamor projected-beamsmokedetectorsare usedinsteadofa chamberwithintheunit:a wall-mountedunitemitsa beam ofinfraredor ultraviolet lightwhichiseitherreceivedandprocessedbya separatedevice,or reflectedbacktothereceiver bya reflector
- 21. • In sometypes, particularly optical beam types, the light emitted by the light source passes through the air being tested and reaches the photo sensor. • The received light intensity will be reducedby absorption due to smoke, air-borne dust, or other substances; the circuitry detects the light intensity and generates the alarm if it is below a specified threshold, potentially due to smoke.
- 22. • In othertypes, typically chamber types, the light is not directed at the sensor, which is not illuminated in the absence of particles. • If the air in the chamber contains particles (smoke or dust), the light is scattered and some of it reaches the sensor, triggering the alarm. 1: Optical chamber 2: Cover 3: Case moulding 4: Photodiode (detector) 5: Infrared LED
- 23. Carbon monoxide andcarbon dioxide detection • Carbon monoxide sensors detect potentially fatal concentrations of carbonmonoxide gas, which may build up due to faulty ventilation where there are combustion appliances such as heaters and cookers, although there is no uncontrolled fire outwith the appliance. • High levels of carbondioxide (CO2) may indicate a fire, and can be detected by a carbondioxide sensor. Such sensors are often used to measurelevels of CO2 which may be undesirable butnot indicative of a fire; this type of sensor can also be used to detect and warn of the much higherlevels generated by a fire.
- 24. Flame detector • Aflame detector is a sensor designed to detect and respond to the presence of a flame orfire. Responses to a detected flame depend on the installation, but can include sounding an alarm,deactivating a fuel line (such as a propane ora natural gas line), and activating a firesuppression system. • When used in applications such as industrial furnaces, their role is to provideconfirmation that the furnace is properly lit; in these cases they take nodirect action beyond notifying the operator orcontrol system. • A flame detector can often respond faster and more accurately than a smokeorheat detector dueto the mechanisms it uses to detect the flame.
- 26. Fire Gas Detector •This detector is mostly used in factories where gas can cause fire and can be dangerous and lethal • Thistype of detector is generallyplaced on the pipes in factories to prevent any kind of leakage.
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- 29. Fire alarm system •A fire alarm system is numberof devices working together todetect and warn people through visual and audio appliances when smoke,fire, carbonmonoxide or other emergenciesare present. • These alarmsmay beactivated from smoke detectors, and heat detectors. Alarms can be either motorized bells or wall mountable sounders orhorns. • They can also be speakerstrobes which sound an alarm, followed bya voiceevacuation messagewhich warn people inside the building notto use the elevators. They may also beactivated via manual fire alarmactivation devices such as manual call points orpull stations. • Firealarm sounders canbe set to certain frequencies and different tones including low, medium and high, depending on the country and manufacturer of the device.
- 30. Parts •Fire alarm controlpanel (FACP) AKA fire alarm control unit (FACU); This component, the hub of the system, monitors inputs and system integrity, controls outputs and relays information. •Primary power supply: Commonly the non-switched 120 or 240 volt alternating current source supplied from a commercial power utility. In non-residential applications, a branch circuit is dedicated to the fire alarm system and its constituents. "Dedicated branch circuits" should not be confused with "Individual branch circuits" which supply energy to a single appliance. •Secondary (backup) power supplies: This component, commonly consisting of sealed lead-acid storage batteries or other emergency sources including generators, is used to supply energy in the event of a primary power failure.
- 31. • Initiating devices:This component acts as an input to the fire alarmcontrol unit and areeither manually or automatically activated. Examples would be devices pull stations, heat detectors, or smoke detectors. Heat and smoke detectors have different categories of both kinds. Somecategories are beam, photoelectrical, aspiration, and duct. • Notification appliances: This component uses energy supplied from the fire alarm system orother stored energy source, to inform the proximate persons of the need to take action, usually to evacuate.This is done by means of a flashing light, strobe light, electromechanical horn, "beeperhorn", chime, bell, speaker, ora combination of these devices. The System Sensor Spectralert Advance Horn makes a beeping sound and electromechanical sound together. Strobes areeithermade of a xenontube (most common),ornowLED lights. • Building safetyinterfaces:This interface allows the fire alarm system to control aspects of the built environment and to preparethe building for fire, and to control the spread of smoke fumes and fire by influencing air movement, lighting, process control, human transport and exit.
- 32. Initiating Devices • Manuallyactuated devices; also known as fire alarm boxes, manual pull stations, orsimply pull stations, break glass stations, call points or buttons. Devices for manual fire alarm activation areinstalled to bereadily located (nearthe exits), identified, and operated. • Automatically actuated devices can take many forms intended torespond to any numberofdetectable physical changes associated with fire: convected thermal energy; heat detector, products of combustion; smoke detector, radiant energy; flame detector, combustion gasses; fire gas detector, and release of extinguishing agents; water-flow detector
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- 34. Notification Appliances • NotificationAppliances utilize audible, visible, tactile, textual orevenolfactory stimuli (odorizer)to alertthe occupants of the need to evacuate or take action in the event of fire orother emergency. • Evacuation signals may consist of simple appliances that transmit encodedinformation, codedappliances that transmit a predetermined pattern, and orappliances that transmit audible and visible textual information such as live orpre-recordedinstructions, and illuminated messagedisplays. • Firealarm evacuationsignals generally consist of a standardized audible tone, with visual notification in all public and common use areas.Emergencysignals are intended to bedistinct and understandable to avoid confusion with other signals.
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- 36. Emergency voice alarmcommunication systems • Somefirealarm systems utilize emergencyvoice alarm communication systems (EVACS) to provide pre- recordedand manual voicemessages. VoiceAlarm systems are typically used in high-rise buildings, arenas and otherlarge "defend-in-place" occupancies such as Hospitals and Detention facilities where total evacuation is difficult to achieve. • Voice-basedsystems provide response personnel with the ability toconduct orderly evacuation and notify building occupants of changing event circumstances. • In high rise buildings, different evacuation messages may beplayed to each floor, depending onthe location of the fire. Thefloor the fire is on along with ones above it may be told to evacuate while floors much lower may simply beasked to stand by.
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- 38. Mass notification systems/emergencycommunication systems • Massnotification systems often extend the notification appliances of a standard fire alarm system to include PC based workstations, text based digital signage, and a variety of remote notification options including email, text message, RSS feed, or IVR based telephone text-to- speech messaging.
- 39. Mass notification systems/emergencycommunicationsystems
- 40. Building safety interfaces •Magnetic smoke door holders • Duct mounted smoke detection • Emergency elevator service • Public address rack(PAR)