Sept 2007/chenck/May20 02/V3 Chapter 2 1 Fire Prevention and Fire Fighting Chapter 2 Chapter 2 Classification of fires Classification of fires How Fire Spreads How Fire Spreads (0.25)
May 25, 2015
Sept 2007/chenck/May2002/V3 Chapter 2 1
Fire Prevention and Fire Fighting
Chapter 2Chapter 2 Classification of fires Classification of fires How Fire SpreadsHow Fire Spreads
(0.25)
Sept 2007/chenck/May2002/V3
Chapter 2 2
Previous Chapter
In chapter 1, you learn all about chemistry In chapter 1, you learn all about chemistry of fire and their propertiesof fire and their properties
In chapter 2, you will understand there are In chapter 2, you will understand there are different types of fire e.g different types of fire e.g Wood fireWood fire Oil fire Oil fire Electrical fire etcElectrical fire etc
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Classifications of fires
There are 4 Classes of firesThere are 4 Classes of fires
Class A FiresClass A Fires Class B FiresClass B Fires Class C FiresClass C Fires Class D FiresClass D Fires
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Classifications of fires
Class A firesClass A fires
Class A fires are wood fires or Class A fires are wood fires or carbonaceous firescarbonaceous fires
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Carbonaceous Fires
Carbonaceous fires are fires that is made Carbonaceous fires are fires that is made majorly of carbon or organic materials egmajorly of carbon or organic materials eg CoalCoal PaperPaper ClothesClothes RopesRopes Rubber etcRubber etc
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Class A Fires
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Classifications of fires
What about oil fires?What about oil fires? What about petrol fires, cooking oil fires?What about petrol fires, cooking oil fires? Fires that come from grease, from tar…Fires that come from grease, from tar… Fires that come from gas – like your those Fires that come from gas – like your those
in your house or cigarette lighter?in your house or cigarette lighter?
How are these fires classified?How are these fires classified?
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Class B Fires
These fires are classified as Class B firesThese fires are classified as Class B fires
Oil firesOil fires Liquid firesLiquid fires Grease firesGrease fires Gas firesGas fires
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Class B Fires
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Class B Fires
Liquid fires are divided into two typesLiquid fires are divided into two types
Oil firesOil fires Liquid firesLiquid fires Grease firesGrease fires Gas firesGas fires
Combustible liquids
Flammable liquids
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Class B Fires
You must remember that only vapour You must remember that only vapour catches firecatches fire
Combustible liquid means you have to heat Combustible liquid means you have to heat the liquid to a point where there is sufficient the liquid to a point where there is sufficient vapour given off to allow ignition e.g. vapour given off to allow ignition e.g. cooking oil, fuel oil, diesel oil etccooking oil, fuel oil, diesel oil etc
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Class B Fires
Flammable Liquid means that it is Flammable Liquid means that it is flammable, it can burn straight away flammable, it can burn straight away
It means there is always sufficient vapour It means there is always sufficient vapour emitted, you don’t have to heat it to get emitted, you don’t have to heat it to get vapourvapour
There is sufficient vapour for immediate There is sufficient vapour for immediate ignition e.g. petrolignition e.g. petrol
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Class B Fires
DiscussionDiscussion A cook is cooking vegetable in a pan. He A cook is cooking vegetable in a pan. He
pours some liquid into the pan and it pours some liquid into the pan and it catches fire immediately . Explain why does catches fire immediately . Explain why does the original oil in the pan does not ignite? the original oil in the pan does not ignite? What did he put into the pan to cause this What did he put into the pan to cause this effect?effect?
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Class C fires
Class C fires are fires involving electricity Class C fires are fires involving electricity i.e. electrical firesi.e. electrical fires
Electrical motorsElectrical motors Electrical switchboardsElectrical switchboards Electrical plugsElectrical plugs Radios, fans etcRadios, fans etc
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Class C Fires
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Class D fires
Involving metalsInvolving metals
Fine metal powderFine metal powder MagnesiumMagnesium PotassiumPotassium Sodium etcSodium etc
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Class D Fires
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Summary on Classes of Fires
Classes of Fire What It Involves
Class A Wood, ropes, clothes, mattress, plastics etc
Class B Oil, gas, grease, fuel oil, diesel oil, petrol, kerosene,
Class C Electrical equipment
Class D Fine metal powder, potassium, sodium, magnesium etc
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Chapter 2 19
How Fire Spread
Fire is spread by an equalization of Fire is spread by an equalization of temperature between two bodies.temperature between two bodies.
There are 3 ways how fire spread.There are 3 ways how fire spread.
ConductionConduction ConvectionConvection RadiationRadiation
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Fire Spread by Conduction
Heat transmission through contact of one Heat transmission through contact of one body to another e.g. metalbody to another e.g. metal
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Fire Spread by Convection
Heat transmission through air or fluid Heat transmission through air or fluid
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Fire Spread by Radiation
Heat transmission through spaceHeat transmission through space
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Summary of how fire spread
ConductionConduction
ConvectionConvection
RadiationRadiation
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Development of Fire
There are 4 phases of fireThere are 4 phases of fire
Ignition Ignition DevelopingDeveloping Absolute fire Absolute fire Burning outBurning out
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4 Phases of Fire
Ignition – the starter (incipient)Ignition – the starter (incipient)
1
Ignition
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4 Phases of Fire
Developing ( surface fires)Developing ( surface fires)
2
developing
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4 Phases of Fire
Absolute Absolute Heat has gone into the depth of the Heat has gone into the depth of the
materialmaterial
3
Absolute fire
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4 Phases of Fire
Most of the fuel has been burned. Fire is Most of the fuel has been burned. Fire is about to be extinguished.about to be extinguished.
4
burning out
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Summary of 4 Phases of Fire
Ignition Ignition DevelopingDeveloping Absolute fire Absolute fire Burning outBurning out
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End of Chapter