What you will learn…
1- Fire Tetrahedron
2- Types of Fires
3- Types of Extinguishers
4- How to Use an Extinguisher
5-Rules for Fires
Fire Tetrahedron
- Air
-Fuel
-Heat
-Chain Reaction
1- Fuel (Combustible Substances)
Combustible substances exist as Solids, Liquids, and gases.
1- Solids: Wood, Paper, Cartons, Cloth
2- Liquids: M. Gasoline, Solvents, Alcohols
3- Gases: Propane, Butane, Acetylene, …
2- Oxygen
All combustible substances need oxygen to burn.
Oxygen is normally available in the air in sufficient quantities (21%).
Lower and upper limits of flammability.
All substances will burn only if the ratio between air and the vapor lies between limits.
3- Heat (Source of Ignition)
-Electricity
-Smoking
-Cutting and Welding
-Open Flames
-Hot Surfaces
-Spontaneous Ignition
-Static Sparks
-Friction
4- Chemical Reaction
Fire occurs when fuel, Oxygen, and heat are present in the right conditions and amounts.
Free Radicals : Chemical chain reaction
Types of Fires
Fires Are Classified by the type FUEL they burn.
The 4 Types are
Class A Fires are occurring in solid such as:Wood,Paper,Rags and Plastic
Class B Fires are occurring in the liquid and gaseous substances such as: gasoline burning cars, kerosene, solvents, alcohols.
Class C Fires Electrical Fires Office Equipment such as: Motors,Switchgear and Heaters
Class D Fires Metals, Potassium,Sodium,Aluminum and Magnesium
Class k Is a kind of modern fires have been newly added to the types of fires and fires that occur regard to vegetable oils kitchens.
Types of Extinguishers
1- Water Fire Ext.
2- Foam Fire Ext.
3- Powder Fire Ext
4- Carbon Dioxide Fire Ext.
5- Halon Fire Ext.
Water Fire Ext.
Used on Wood, Paper, Plastic
Class A Fires
Foam Fire Ext.
Used on Flammable Liquid Fires
Powder Fire Ext.
Used for class A fires, Class B fire.
Recommended not to be used in electrical fires.
Absorbs free radicals on surface.
Powder Fire Extinguisher:Used for class A fires, Class B fire, and class C fires
Carbon Dioxide Fire Ext.
Used for class B fires and class C fires.
Halon Fire Ext.
Used for class B and Class C fires.
Do not leave any residues and React with the free radicals of the fire.
Using A Fire Extinguisher
1)Pull the Pin
This will allow you to discharge the extinguisher.
2)Aim at the base of the fire.
3)Squeeze the top handle or lever.
This depresses a button that releases the pressurized extinguishing agent in the extinguisher
4)Sweep from side to side until the fire is completely out.
Extinguishing The Fire
1- Starvation: Starve the fire by depriving it of flammable materials, which is the fuel for the fire nutritious and that the transfer of goods and materials available place the fire away from the influence of heat and flame. It can also pull the flammable liquids from tanks located by the fire.
2- Smothering: Smother the fire to mute the flames and prevent access of oxygen to her, and this is done either to cover the fire Foams or use carbon dioxide, which replaces oxygen as well as using halon or powder.
3- Cooling: Fire cooling to reduce the temperature and this is the most common way in fire-fighting water, using this method depends mainly on the ability of water to absorb the heat of the burning material
4- Stop the chain reaction: Some of the materials firefighters the ability to stop the chain reaction of the fire, this material is a powder and halon.
Rules for Fighting Fires
- Fight fire in up wind direction.
-Start fighting the fire from safe distance (2 – 5 m) away.
-Direct the stream to the base of the fire.
-Sweep the stream from side to side.
-Do not leave the fire area unless you are sure that the fire is completely out.
