3. FIRE
• Fire is the 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 FIRE SPREAD?
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:
• Always usea 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.
10. Detection
• Fire detectorssense one 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
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 heat detectors
• 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.
16. Smoke detector
• A smokedetector 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.
18. Types of smoke detectors
• 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.
21. • In some types, 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 other types, 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 and carbon 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
• A flame 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.
25.
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.
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 control panel (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
• Manually actuated 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
34. Notification Appliances
• Notification Appliances 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.
36. Emergency voice alarm communication 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.
38. Mass notification systems/emergency communication
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.
