Fire Extinguishment Theory
Course
Firefighter I
Unit III
Live Fire
Essential
Question
Why is it
important for
firefighters to
have an
understanding of
fire behavior that
determines the
appropriate
tactics and
strategies to
effectively
control and
extinguish fire?
TEKS
§130.299(c)
(8)(A)(B)
(9)(A)(B)(C)
Prior Student
Learning
Completed
assigned
reading and use
of previous
knowledge,
skills, and
experience
Estimated Time
4 to 6 hours
Rationale
It is necessary for firefighters to understand the separate and distinct modes
of combustion in which fuel burns (smoldering or flaming). Fire is controlled
and extinguished by disrupting or limiting one, or more elements of the
combustion process. In essence, fire is extinguished or controlled by
removing heat, fuel, or oxygen from the combustion process, or by
interrupting the self-sustained chemical chain reaction that occurs when a
fire is in the flaming mode of combustion.
Objectives
The student will be able to:
1. Explain the fire extinguishment theory
2. Analyze methods of extinguishment such as temperature reduction,
fuel removal, oxygen exclusion, and inhibiting the chemical chain
reaction
3. Describe the characteristics of water as related to fire extinguishment
4. Explain the Law of Heat Flow, the Law of Specific Heat, and the Law
of Latent Heat of Vaporization
5. Compare the advantages and disadvantages of water as an
extinguishing agent
Engage
Engage the students in a discussion about the need to appreciate and
understand how fire is controlled. Understanding the chemical and physical
properties of fire helps determine what the fire may do, and allows
firefighters to choose effective strategies and tactics to extinguish or control
fires. Use the Discussion Rubric for assessment.
Key Points
I. Definitions
A. Fire – a rapid, self-sustaining oxidation process accompanied by the
evolution of heat and light
B. Combustion – a chemical reaction that releases energy as heat and
usually light. When a substance is undergoing combustion, it is
usually referred to as being “on fire.”
C. Oxidation – the chemical combination of any substance with an
oxidizer
D. Oxidizer – a substance that gains electrons in a chemical reaction.
E. Energy – the capacity for doing work
II. The Fire Triangle/Fire Tetrahedron
A. Originally, fire was thought to be based on the presence of three
elements, or sides, of a Fire Triangle:
1. Fuel
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2. Air
3. Heat
B. From a scientific standpoint, based on chemistry and physics, the
three elements or sides of the fire triangle should be:
1. Fuel
2. Oxidizer (air)
3. Energy (heat)
C. It was and still is commonly believed that fire can be extinguished or
controlled by removing one of the three elements and eliminating the
triangle. This is true, but only for fires in a smoldering mode of
combustion.
D. Scientists have since determined that there is a fourth component to
fire called a chemical chain reaction.
1. Molecules are broken down by heat, producing free radicals.
2. Free radicals combine with the oxidizer.
3. The process produces more heat and more free radicals, and the
process continues.
4. As long as there are ample amounts of fuel, oxidizer, and
energy, the combustion process continues until it is interrupted.
E. The discovery of this fourth component requires firefighters to
recognize the four planes of a tetrahedron when considering
extinguishment options:
1. Fuel
2. Oxidizer (air)
3. Energy (heat)
4. Chemical chain reaction
III. Fuel Removal
A. Eliminating the fuel source effectively extinguishes any fire.
B. Eliminating the fuel source can be accomplished by
1. Allowing the fire to burn until all the fuel is consumed
2. Shutting off or removing the source of the fuel supply
3. Closing a valve (liquid or gaseous fuels)
4. Removing solid fuels in the path of the fire (i.e. wildland fires)
IV. Oxygen Exclusion
A. Removing or reducing available oxygen from the combustion
process will reduce a fire’s growth, and in most cases, extinguish the
fire over time.
B. Some examples of oxygen removal are
1. Placing a cover on a pan of burning grease
2. Using a carbon dioxide (CO2) extinguisher to displace the oxygen
in a confined space and disrupt the combustion process
3. Using a foam blanket to separate flammable liquids from the
atmosphere
C. None of the above methods will work with fuels that are selfoxidizing.
V. Temperature Reduction
A. The temperature of the fuel must be reduced to a point where the
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fuel ceases to produce flammable vapors.
B. The most common method of temperature reduction used to
extinguish or control fires is cooling the fire with the application of
water.
C. Cooling with water is the most effective method available for use on
smoldering fires.
D. Water must be applied in sufficient amounts to absorb the heat
being generated by the combustion process.
E. Cooling with water cannot sufficiently reduce the amount of vapors
produced in fires involving low flashpoint flammable liquids and
gases.
F. Water has its greatest cooling effect when it is vaporized and
converted into steam.
G. Water expands to 1700 times its original volume when converted to
steam at 212 degrees Fahrenheit (F).
H. Beware of excess steam production. It can make the situation less
tenable for firefighters by making it more difficult to see, and
increasing the chances of steam burns.
VI. Chemical Flame Inhibition
A. Some extinguishing agents, including some dry chemical
extinguishers, some halogenated agents (halons), and the new
replacement agents, interrupt the combustion process by limiting the
production of free radicals.
B. Chemical flame inhibition is most effective on gaseous and liquid
fuel fires in the flaming mode of combustion.
C. Chemical flame inhibition is less effective on fires in the smoldering
mode of combustion, to the point that the concentration of
extinguishing agent necessary and the amount of time involved
makes the attempt impractical.
VII. The Extinguishing Properties of Water
A. Can extinguish fire in different ways:
1. Extinguishes by cooling (heat absorption)
2. Extinguishes by smothering, diluting, or excluding oxygen
3. Extinguishes by heat absorption (converting into water vapor or
steam)
B. Readily available and is inexpensive (relatively)
C. Greater heat absorbing capacity than most other common agents
D. Changing into steam requires a relatively large amount of heat
(latent heat of vaporization)
E. Expands to 1700 times its original volume when converted to steam
at 212 degrees F
1. Absorbs more heat faster, and cools the fuel below its ignition
temperature
2. Displaces hot gases, smoke, and other products of combustion
3. In some cases, the steam smothers the fire through oxygen
exclusion
F. Can be applied in many different ways
1. Solid stream
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2. Fog stream
3. Straight stream
4. Narrow pattern
5. Wide pattern
6. Broken stream
G. Can be used as a cooling agent for protecting exposures
VIII. Law of Specific Heat
A. Specific heat –the amount of heat needed to raise the temperature
of a specific mass of a substance 1 degree
B. BTU/British Thermal Unit – the amount of heat needed to raise the
temperature of 1 pound of water by 1 degree F
C. Calorie – the amount of heat needed to raise the temperature of 1
gram of water by 1 degree Celsius
D. Water has a high specific heat (greater heat-absorbing capacity)
than most other common extinguishing agents
IX. Law of Latent Heat
A. Latent heat – the amount of energy it takes to melt or boil a certain
amount of material.
B. A pound of water will absorb
1. 1 BTU for every degree F it is raised, until it reaches its boiling
point (212 degrees F)
2. An additional 970 BTUs as it is completely converted to steam
(latent heat of vaporization)
3. Example: A pound of water having its temperature raised from 80
degrees F to full steam conversion absorbs 1,102 BTUs (132
BTUs going from 80F to 212F, plus an additional 970 BTUs as it
is converted to steam)
C. A gallon of water will absorb
1. 8.33 BTUs for every degree F it is raised, until it reaches its
boiling point (212 degrees F)
2. A gallon of water will absorb an additional 8,080 BTUS as it is
completely converted to steam (latent heat of vaporization)
3. Example: A gallon of water having its temperature raised from 80
degrees F to full steam conversion absorbs 9,179.56 BTUs
(1,099.56 BTUs going from 80F to 212F, plus an additional 8080
BTUs as it is converted to steam)
D. Because of its ability to absorb heat, water is a very effective
extinguishing agent.
X. Law of Heat Flow
A. The second law of thermodynamics
B. Heat flows from a hot substance to a cold substance, but not the
other way around.
1. When you put ice in a warm glass of water, the water melts the
ice.
2. When it snows, the warm ground will melt the snow.
3. When water is applied to a fire, the heat of the fire raises the
temperature of the water being applied.
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XI. Advantages and Disadvantages of Using Water as the Primary
Extinguishing Agent
A. Advantages
1. Availability
2. Affordability
3. Effectiveness
4. Easily stored
5. Can be transported long distances
B. Disadvantages
1. Water is relatively heavy; it weighs 8.33 pounds per gallon
2. Directing master streams into buildings can result in heavy
accumulations of water in the structure, increasing the potential
for structural collapse.
3. Water and water-based extinguishing agents cannot safely be
used on Class C fires until the electrical energy has been
eliminated.
4. Water applied to a combustible metal fire can result in a violent
reaction that could intensify the combustion process.
Activities
1. Students will participate in fire extinguishing classes with a practical
exercise in extinguishing Class A and Class B fires. Use the Operate
a Fog-Stream Nozzle (Narrow Stream) Checklist and the Operate a
Fog-Stream Nozzle (Straight Stream) Checklist for assessment.
2. Students will do math calculations determining the number of BTUs
absorbed by various amounts of water from varying ambient
temperatures through the complete conversion of steam. Use the
Individual Work Rubric for assessment.
Assessments
Fire Extinguishment Theory Quiz and Key
Operate a Fog-Stream Nozzle (Narrow Stream) Checklist
Operate a Fog-Stream Nozzle (Straight Stream) Checklist
Discussion Rubric
Individual Work Rubric
Materials
Fire Extinguishment Theory computer-based presentation
Computers with Internet access
Resources
1418001775, Introduction to Fire Protection (3rd Edition), Klinoff, Robert
0135151112, Essentials of Firefighting (5thEdition), International Fire
Service Training Association (IFSTA)
Accommodations For Learning Differences
For reinforcement, students will participate in peer teaching (mentoring) and
team learning, participate in guided research and note-taking (web based),
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and keep journals (key words and definitions).
For enrichment, students will participate in training evaluations, including,
but not limited to, fire extinguisher training and operating hand lines.
State Educational Standards
Texas Essential Knowledge and Skills for Career and Technical Education
130.299 Firefighter I (One to Two Credits).
(8) The student comprehends the fire extinguishment theory. The student
is expected to:
(A) Describe the fire extinguishment theory; and
(B) Analyze methods of extinguishment such as temperature reduction,
fuel removal, oxygen exclusion, and inhibiting chemical reaction.
(9) The student describes the characteristics of water as it relates to fire
extinguishing potential. The student is expected to:
(A) Describe the physical characteristics of water;
(B) Explain the Law of Specific Heat, the Law of Latent Heat, and the
Law of Heat Flow; and
(C) Compare the advantages and disadvantages of water as an
extinguishing agent.
College and Career Readiness Standards
Science
I. Nature of Science: Scientific Ways of Learning and Thinking
C. Collaborative and safe working practices
1. Collaborate on joint projects.
2. Understand and apply safe procedures in the laboratory and field,
including chemical, electrical, and fire safety and safe handling of
live or preserved organisms.
3. Demonstrate skill in the safe use of a wide variety of apparatuses,
equipment, techniques, and procedures.
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Name:_________________________
Date:___________________________
Fire Extinguishment Theory Quiz
1. _____The fire tetrahedron has ____ planes, each representing a separate component.
a. 2
b. 3
c. 4
d. 5
2. _____Water expands to ______ times its original volume when it is completely converted
to steam.
a. 900
b. 1200
c. 1300
d. 1700
3. _____The boiling point of water is _____ degrees Fahrenheit.
a. 100
b. 180
c. 200
d. 212
4. _____A pound of water will absorb an additional _____ BTUs as it is completely
converted to steam.
a. 970
b. 1150
c. 1200
d. 160
5. _____The Law of Heat Flow is the ____ law of thermodynamics.
a. 1st
b. 2nd
c. 3rd
d. 4th
6. _____A gallon of water weighs approximately _____ pounds.
a. 7.50
b. 8.33
c. 11.00
d. 9.70
7. _____Chemical flame inhibition is most effective on which mode of combustion?
a. Smoldering
b. Decay
c. Oxygen controlled
d. Flaming
8. _____Which of the following is not an advantage of using water as an extinguishing
agent?
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a. Availability
b. Affordability
c. Effectiveness
d. Relatively lightweight
9. _____Which of the following statements is false?
a. When water is applied to a fire, the heat of the fire raises the temperature of the
water being applied.
b. Directing master streams into buildings can result in heavy accumulations of
water in the structure, increasing the potential for structural collapse.
c. Water and water-based extinguishing agents can safely be used on Class C
fires while the electrical energy is connected.
d. Water applied to a combustible metal fire can result in a violent reaction that
could intensify the combustion process.
10. _____ A gallon of water will absorb an additional _____ BTUs as it is completely
converted to steam.
a. 6060
b. 7070
c. 8080
d. 9090
11. _____Specific heat is the amount of heat needed to raise the temperature of a specific
mass of a substance ____degree(s).
a. 1
b. 5
c. 10
d. None of the above
12. _____Fire is defined as:
a. A chemical reaction that releases energy as heat and usually light.
b. The chemical combination of any substance with an oxidizer.
c. A rapid, self-sustaining oxidation process accompanied by the evolution of heat
and light.
d. None of the above
13. _____As long as there are ample amounts of fuel, oxidizer, and energy, the combustion
process continues until it is interrupted.
a. True
b. False
14. _____Extinguishing a fire by oxygen removal is not effective with fuels that are selfoxidizing.
a. True
b. False
15. _____When a substance is undergoing combustion it is usually referred to as “being on
fire.”
a. True
b. False
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16. _____An accelerator is a substance that gains electrons in a chemical reaction.
a. True
b. False
17. _____Eliminating the fuel source effectively extinguishes any fire.
a. True
b. False
18. _____ Removing or reducing available oxygen from the combustion process will increase
a fire’s growth, and in most cases, extinguish the fire over time.
a. True
b. False
19. _____Chemical flame inhibition is most effective on fires in the flaming mode of
combustion.
a. True
b. False
20. _____The most common method of temperature reduction used to extinguish or control
fires is cooling the fire with the application of Carbon Dioxide (C2O).
a. True
b. False
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Fire Extinguishment Theory Quiz Key
1. C
2. D
3. D
4. A
5. B
6. B
7. D
8. D
9. C
10. C
11. A
12. C
13. A
14. A
15. A
16. B
17. A
18. B
19. A
20. B
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Name:_________________________
Date:___________________________
Operate a Fog-Stream Nozzle
Narrow Stream
1 pt.
each
Performance Objectives
Positions him or herself on the same side of the hose with an additional
student as backup
Prior to opening the nozzle, waits for his or her backup to communicate that
they are ready
Twists the stream adjustment ring to adjust the stream pattern to a narrow
stream
Aims the nozzle at the target, as indicated by the instructor, and opens the
nozzle fully, holding the stream for 15 seconds
Shuts the nozzle off so that a water hammer is avoided
Total points possible 5
Instructor’s Signature
Date
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Name:_________________________
Date:___________________________
Operate a Fog-Stream Nozzle
Straight Stream
1 pt.
each
Performance Objectives
Positions him or herself on the same side of the hose
with an additional student as backup
Prior to opening the nozzle, waits for his or her backup to
communicate that they are ready
Twists the stream adjustment ring to adjust the stream
pattern to a straight stream
Aims the nozzle at the target, as indicated by the instructor,
and opens the nozzle fully, holding the stream for 15 seconds
Shuts the nozzle off so that a water hammer is avoided
Total points possible 5
Instructor’s Signature
Date
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Name_______________________________________
Date_______________________________
Discussion Rubric
Objectives
4 pts.
Excellent
3 pts.
Good
2 pts. Needs Some
Improvement
1 pt. Needs Much
Improvement
N/A
Pts.
Participates in group discussion
Encourages others to join the
conversation
Keeps the discussion progressing
to achieve goals
Shares thoughts actively while
offering helpful recommendations to
others
Gives credit to others for their ideas
Respects the opinions of others
Involves others by asking questions
or requesting input
Expresses thoughts and ideas
clearly and effectively
Total Points (32 pts.)
Comments:
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Name______________________________________
Date_______________________________________
Individual Work Rubric
4 pts.
Excellent
Objectives
3 pts.
Good
2 pts. Needs Some
Improvement
1 pt. Needs Much
Improvement
N/A
Pts.
Follows directions
Student completed the work as directed,
following the directions given, in order and to the
level of quality indicated
Time management
Student used time wisely and remained on task
100% of the time
Organization
Student kept notes and materials in a neat,
legible, and organized manner. Information was
readily retrieved
Evidence of learning
Student documented information in his or her
own words and can accurately answer questions
related to the information retrieved
*Research/Gathering information (if relevant)
Student used a variety of methods and sources
to gather information. Student took notes while
gathering information
Total Points (20 pts.)
Comments:
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