chapter 2 classes & spread

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

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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


Chapter 2 3

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


Chapter 2 4


Class A firesClass A fires

Class A fires are wood fires or Class A fires are wood fires or carbonaceous firescarbonaceous fires


Chapter 2 5

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


Chapter 2 6

Class A Fires


Chapter 2 7


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?


Chapter 2 8

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


Chapter 2 9

Class B Fires


Chapter 2 10

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


Chapter 2 11

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


Chapter 2 12

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


Chapter 2 13

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?


Chapter 2 14

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


Chapter 2 15

Class C Fires


Chapter 2 16

Class D fires

Involving metalsInvolving metals

Fine metal powderFine metal powder MagnesiumMagnesium PotassiumPotassium Sodium etcSodium etc


Chapter 2 17

Class D Fires


Chapter 2 18

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


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


Chapter 2 20

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


Chapter 2 21

Fire Spread by Convection

Heat transmission through air or fluid Heat transmission through air or fluid


Chapter 2 22

Fire Spread by Radiation

Heat transmission through spaceHeat transmission through space


Chapter 2 23

Summary of how fire spread

ConductionConduction

ConvectionConvection

RadiationRadiation


Chapter 2 24

Development of Fire

There are 4 phases of fireThere are 4 phases of fire

Ignition Ignition DevelopingDeveloping Absolute fire Absolute fire Burning outBurning out


Chapter 2 25

4 Phases of Fire

Ignition – the starter (incipient)Ignition – the starter (incipient)

1

Ignition


Chapter 2 26

4 Phases of Fire

Developing ( surface fires)Developing ( surface fires)

2

developing


Chapter 2 27

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


Chapter 2 28

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


Chapter 2 29

Summary of 4 Phases of Fire

Ignition Ignition DevelopingDeveloping Absolute fire Absolute fire Burning outBurning out


Chapter 2 30

End of Chapter

chapter 2 classes & spread

Business

class b fires liquid

class c fires class

wood fires

classifications of fires

classes of fires class

petrol fires

classification of fires

tar fires