This document provides an overview of fire, including its definition, causes, outcomes, classes, stages, combustion theory, and firefighting mechanisms. It defines fire as a rapid oxidation chemical reaction and notes that fires usually start small due to sparks from neglecting prevention. The main outcomes of fire are combustion gases, heat, flames, and smoke. Fires can be caused by human carelessness, natural causes, or technical failures. Combustion requires fuel, oxygen, heat, and a chain reaction. Firefighting works by removing one of these factors through starvation, smothering, cooling, or stopping the chain reaction.

1. Fire
• Omar Anwar ElGanzoury And Kamal Ragheb | Prof. Dr. Mohamed Saad |

2. Project Overview
Combustion Theory Fire Fighting
Flammability
Limits
Fire
Classes
Fire
Hazards
Fire
Causes
Fire
Outcomes
Fire
Stages
Introduction

3. Introduction
 What is FIRE ?
 Fire is a chemical reaction that includes the rapid oxidation of flammable
substances .
The fires usually start on a small scale because most of them originate from
small sparks because of the neglect of fire prevention methods

4. Fire
Hazards
 Personnel Hazard
risk to the lives of individuals for
injuries, suffocation and possibly
death.
 Damage Hazard
destruction of buildings and
structures due to the fire.
 Exposure Hazard
risks that Threats to nearby sites ,
There is no requirement for direct
contact between the fire and the
building at risk.
 Environmental Pollution
Fire is often associated with
catastrophic environmental damage,
especially in oil installations.
Personnel
Hazard
Damage
Hazard
Exposure
Hazard
Environmental
Pollution

5. Combustion
Gases
Heat
Flame
Smoke
Fire Outcomes
Fire
Outcomes
 Combustion Gases
Combustion gases are the most
common causes of death during fire,
and inhalation leads to rapid
suffocation, especially if these gases
are toxic, hot or oxygen free.
 Heat
The temperature is responsible for the
speed of ignition and the spread of fire,
and its effects on human dryness of the
skin and difficulty breathing, as well as
its destructive effects on the buildings.
 Flame
The flame is the light accompanying
the heat.
 Smoke
Smoke is the result of incomplete
ignition of materials, a combination of
small components of non-burnt solids
with resulting gases and condensate
fumes.

6. Fire Causes
Technical
Causes
Natural
Causes
Human
Causes
Fire
Causes
 Human Causes
1. Careless
2. Misuse
3. Premeditation
 Natural Causes
Energy sources that humans
do not have the ability to
control but which have the
ability to protect against some
of their risks .
 Technical Causes
Specifications and standards of
tools and devices used.

7. Combustion
Theory
 Fire Tetrahedron
1. Fuel (Combustible Substances).
2. Air (Oxygen).
3. Heat (Sources of Ignition).
4. Chain Chemical Reaction.
Heat
Oxygen
Chain
Chemical
Reaction
Fuel

8. Combustion Theory
Fuel:
 What burn is the vapors of fuel ( liquid ), and this vapors if combined with the air in
the right ratio of each material and found a source of ignition to burn.
 Example:
1. Solid ( wood, cloth, paper).
2. Liquid ( petroleum liquids (oil, benzene, kerosene, solar, etc…).
3. Gas ( petroleum gases (natural gas, butane, acetylene, hydrogen).

9. Combustion Theory
Air (Oxygen):
 All the materials need Oxygen to burn, the ratio of oxygen in the atmosphere is
about 21%, and the ratio of oxygen should not be less than 16% until the fire
continues.

10. Combustion Theory
Heat (Sources of Ignition)
 Heat is a form of energy that reflects the movement of atoms within an object,
which is invisible but can be felt around us.
• Ignition Point
 Is the lowest temperature where the flammable material releases sufficient amount of
vapors or gases to be with the air sufficiently mixed to ignite and continue to ignite even
after removing the source of ignition
• Flash Point
 Is the lowest temperature in which the flammable liquid releases a quantity of vapors to
be mixed with air and ignites in a flashy image when exposed to a heat source that ends
when this source is removed.

11. Combustion Theory
Many sources of Ignition:
 Electricity:
 Electrical power is one of the essentials of any production site and this danger is
present in electrical connections.
 Ex
1. Overload
2. Do not connect wires properly
3. Damage to electrical wiring or damage to its insulation.
 Smoking:
 Smoking comes in second place after electricity, and most of these fires occur due to the
fall of cigarettes or Residues of burning cigarettes .

12. Combustion Theory
Many sources of Ignition:
 Hot Works:
 Fires occur due to hot works such as cutting and welding in places containing flammable
materials due to sparks.
 Naked Flame:
 Hot Surfaces:
 It is the heat generated from the surfaces of furnaces, boilers, hot pipes and electric lamps.
 Static Electricity:
 Static electricity is produced as a result of friction between two things, one fixed and the other
moving, such as the movement of petroleum materials in pipes, resulting in electrical charges so
it’s necessary to earthing all equipment.
 Friction:
 In the event of friction between the parts of the engines, there may be a rise in temperature that
may cause the ignition of flammable materials close to these equipment and machines.

13. Combustion Theory
 Chain Chemical Reaction:
 The fire continues to ignite as long as the three elements ( material, heat and oxygen)
 are present in the correct proportions, the reaction of these elements produce free
 radicals Which make the continuation of the fire.

14. Explosive
/Flammability Limits
 Explosive/Flammability Limits
• The ignition / explosion limits are the percentage of the volume of flammable
/explosive gases in the air
 Lower Explosive/Flammability Limit(LEL)
• Is the lowest proportion of flammable fumes that combine with the air to form an
explosive / flammable mixture ignites when exposed to ignition source.When there is
a mixture between the air and flammable material below the lower flammability of that
substance, it does not ignite ( poor Mixture ).
 ■ Upper Explosive/Flammability Limit (UEL)
• Is the highest percentage of flammable fumes that combine with the air to form an
explosive / flammable mixture ignites when exposed to a source of ignition. When
there is a mixture between the air and flammable material that is greater than the
maximum flammability of that substance, it does not ignite ( Rich Mixture ).
 The higher the range between LEL & UEL, the greater the
risk of the material.
Lower
Explosive/Flammability
Limit(LEL)
Upper
Explosive/Flammability
Limit (UEL)

15. Fire Classes
 There are five classes of fires according to the US classification depend on the type
of fuel.
 Class A:
 Fire in solid materials such as wood, paper, clothing, rubber and some plastics.
 Class B:
 Fires that occur in liquid and gaseous substances such as oil and petroleum gases.
 Class C:
 Fire originated in equipment, appliances and electrical equipment.
 Class D:
 Fire originated in active minerals such as sodium, potassium and magnesium.
 Class K:
 Fires that occur at kitchens

16. Fire Stages
Ignition
stage
Fire
Growth
stage
Fully
Developed
stage
Decay/
Burn out
stage

17. Fire Stages
 Ignition stage
 At this stage the combustible materials are combined with oxygen and heat (ignition source)
in a chain chemical reaction as a result of generating free radicals.
 The fire begins to appear as smoke, and may develop rapidly at this stage or slowly over a
period of time that may not exceed a few minutes.
 At this stage no heat or flame is observed, and the fire can be controlled using handheld fire
extinguishers.
 Some substances, such as gases, may not pass through this stage and there is a sudden
explosion as soon as there is a source of ignition.
 Fire Growth stage
 The flame begins to appear as a source of heat. More flammable materials are burned.
 Convection and radiation currents start to heat more surfaces to reach the ignition point .

18. Fire Stages
 Fully Developed stage
 At this stage, the fire is fully developed and reaches its peak, and all the flammable
materials available are burned with extreme temperatures, which can result in serious
damage to the place with the rapid consumption of oxygen.
 Decay/ Burn out stage
 At this point, the fire reduces or loses flammable or oxygen content. The fire then decreases and the
temperatures begin to drop. The fire begins to eat itself until
it is extinguished and turned into ash.

19. Conduction
 The heat is transferred by direct contact or through the
conductor, as with hot hand contact with hot water. The
heat passes from the container to the hand through the
connector.
Convection
 Heat travels in liquids and gases due to variations in
density depending on temperature changes. Moved by
convection currents and moving from bottom to top
Note : Convection currents happen only in liquids and
gases, not in solid objects.
Radiation
 Heat radiation from hot objects to other less heat
through the air moves in straight lines that propagate in
all directions in the form of heat waves .
Heat Transfer
Methods
Conduction
ConvectionRadiation

20.  To extinguish any type of fire, one
of the four factors that cause fire
( fuel, oxygen, heat and Chemical
chain reaction ) must be
removed.
Fire
Starvation
Fire
Smothering
Fire
Cooling
Chain
Reaction
Stopping
Fire Fighting
Mechanism

21. Fire Fighting Mechanism
 Fire Starvation
 Starving the fire is by depriving it of flammable materials that are fuel for the fire by :
1. Transportation of goods and materials available in the fire place away from the effect of heat
2. Close gas line valves
 Fire Smothering
 The fire is smothering by prevent air oxygen from reaching it .
1. Close outlets and ventilation openings in the fire place
2. Cover flammable materials by chemical foams
3. Replace oxygen with water vapor, carbon dioxide, dry chemical powder, or halogen vapors
4. Fire can be extinguished using explosives such as dynamite. This was the way to extinguish
the oil well fires in the past .

22. Combustion Theory
 Fire Cooling
 Its purpose is to reduce the temperature of flammable materials by using water .
 Chain Reaction Stopping
 For some fire extinguishers estimated to stop the chemical reaction of the fire
sequence, these substances include dry powder and halons. Powder particles absorb
free radicals