Lesson-1-Fire-tech

COURSE CODE: CDI 206
COURSE TITLE: FIE PROTECTION AND ARSON INVESTIGATION
MODULE 1/LESSON 1
LESSON 1
Fire: Its Properties and Elements
Introduction
Fire is both beneficial and dangerous to mankind, when it is properly used it can
serve a lot of benefits to the people but if wrongfully use it may cause great destruction
not only to property but even to security and life. This lesson will focus on discussing the
nature of fire, its properties and elements.
Learning Objectives:
This lesson aims to facilitate student-learners to:
1. Understand the nature and properties of fire;

2. Enumerate and discuss the elements of fire; and
3. Explain the chemical
Learning Content:
I. Fire, Defined
Fire is the rapid oxidation of a material (the fuel) in

the exothermic chemical process of combustion, releasing heat, light, and
various reaction products.
It is the manifestation of rapid chemical reaction occurring between a
combustible matter and an oxidizer.
This reaction releases energy in the form of heat and light.
Fire is an important process.
A. Physical Properties of Fire

1. Specific Gravity – the ratio of the weight of a solid or liquid substance
to the weight of an equal volume of water.
2. Vapor density – the weight of a volume of pure gas compare to the
volume of dry air at the same temperature and pressure.
3. Vapor Pressure – the force exerted by the molecules on the surface of
a liquid.
4. Temperature – the measure of the degree of thermal agitation of
molecules.
5. Boiling Point – the constant temperature at which the vapor pressure of
the liquid is equal to the atmospheric pressure.
6. Flash point – the temperature at which a flammable liquid forms a
vapor-air mixture that ignites (mixture with in the explosive range).
7. Ignition/Kindling temperature – the minimum temperature at which the
substance must be heated in order to initiate combustion.
8. Fire point – the lowest temperature of a liquid in an open container at
which vapors are evolved fast enough to support combustion.
B. Chemical Reactions
Fire is a product of the chemical reaction called combustion. At
certain point of combustion, when the ignition or kindling temperature is
reach, flames are produced which is primarily consist of carbon dioxide,
water vapor, oxygen and nitrogen. Other chemical reactions relative to the
reaction of oxygen to a given material like fuel are:
1. Oxidation – a chemical change that is exothermic, a change in
which combustible material (fuel) and an oxidizing agent (air),
react. Example of oxidation is combustion which is the same as
actual burning (rapid oxidation)
2. Combustion – rapid chemical (oxidation) combination of a
substance with oxygen, involving the production of heat and
light.
3. Ignition – a much faster oxidation which initiates combustion.
4. Explosion – he sudden and violent release of mechanical,
chemical or nuclear energy from a confined space which
creates a heat wave that travels at subsonic speeds. Often used
interchangeably with detonation.
C. Chemical Properties:
1. Endothermic Reactions – changes whereby energy (heat) is absorbed or is
added before the reaction takes place.
Examples:
a. Melting – it is the process by which solid turns into liquid state.
It happens when we get an ice and place it in a warm room or
place. The heat energy coming from the room is absorbed by
the ice making it possible to break out from the force of
attraction that causes it to become is a fixed position thus, it
melt down into water.
b. Vaporization – It is the process by which liquid water gain
enough heat energy to completely overcome the force of
attraction between them and change into gaseous state. This
happen when a water is heated at such temperature reaching its
boiling point, releasing a bubble and escape as a steam.
c. Sublimation – It is a process by which solids directly change into
gaseous state which happens when the solid absorbs enough
energy to completely overcome the force of attraction between
them. A good example of this is the dry ice that undergo
sublimation.
2. Exothermic Reactions – those that release or give off energy (heat) thus they
produce substances with less energy than the reactants.
Examples:
a. Freezing – It is the process by which
a liquid change to solid phase. A
warm water that is placed inside a
freezer loses heat energy until such
time that no energy is available for
the particles to slide past each other
causing the particles to be at fixed
position, locked in place by the force of attraction between them.
b. Condensation – It is the process by which substances in
gaseous state change into liquid form. An example of this is
when taking a hot shower, when the hot water vaporized and it
falls into a cooler surface like for instance a class or mirror, the
vapors that comes in contact with cooler surface will loss heat
energy until such time that it has no energy against the force of
attraction.
c. Combustion of fuel – the combustion of fuel at first is an
endothermic reaction since the fuel will absorbs the heat until
such time that is reaches its flash point to vaporize and its
ignition point to start a combustion, while the fuel is burning it
will release energy in a form of heat and light, this is the
exothermic reaction.
The Pyrolysis
With all elements of fire present, combustion takes place. Before a fuel will
burn, it must be changed to its vapour state. This change usually results from the
initial application of heat known as PYROLYSIS.
Pyrolysis (thermal decomposition) - “chemical decomposition of matter
through the action of heat”. In this case, the decomposition causes a change
from a solid state to vapour state. Of the vapour mixes sufficiently with air and
heated to high temperature, combustion results.
To burn a fuel, its temperature must be raised (increased) until ignition
point. Before a combustible matter starts to burn, it has to be exposed to a
certain degree of temperature.
When the temperature is very high, it releases highly combustible vapors
known as FREE RADICALS (combustible vapors such as Hydrogen gas, Carbon
monoxide, Carbon dioxide, and Nitrogen).
D. The Elements of Fire or the Fire Triangle.

References:
What Is Fire Made Of? Chemical Composition (thoughtco.com) By

Anne Marie Helmenstine, Ph.D.
https://www.chemicool.com/definition/explosion.html
Endothermic and Exothermic Chemical Reactions (thoughtco.com), By

Anne Marie Helmenstine, Ph.D. Updated on September 12, 2019

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COURSE CODE: CDI 206

COURSE TITLE: FIE PROTECTION AND ARSON INVESTIGATION

Fire: Its Properties and Elements

This lesson aims to facilitate student-learners to:

1. Understand the nature and properties of fire;

Fire is the rapid oxidation of a material (the fuel) in

A. Physical Properties of Fire

D. The Elements of Fire or the Fire Triangle.

What Is Fire Made Of? Chemical Composition (thoughtco.com) By

Endothermic and Exothermic Chemical Reactions (thoughtco.com), By

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