Fire Behavior
Course
Firefighter I
Unit V
Fire Behavior
Essential
Question
Why is it
imperative that
firefighters
understand the
combustion
process and the
stages of fire in
order to
effectively
manage fire
emergencies?
TEKS
§130.299(c)
(5)(C)(F)
Prior Student
Learning
Completed
assigned
reading and
previous
knowledge,
skills, and
experience.
Estimated Time
3 to 6 hours
Rationale
Firefighters need to understand fire and its behavior in order to anticipate fire
conditions (during development and extinguishment) that may change
rapidly and risk firefighter safety. Some conditions require a reassessment of
strategies and tactics to accomplish the action plan.
Objectives
The student will be able to:
1. Understand basic fire behavior
2. Identify the stages of fire development
3. Explain the visual indicators of a backdraft
4. Check a door for heat safely while donning personal protective
equipment (PPE)
5. Check the heat level in a room safely while donning PPE
Engage
Have the students watch backdraft training videos. (Note: To find the videos
conduct an Internet search for the following key words: “Backdraft Training
Part One CTFireCop” and “Backdraft Training Part Two CTFireCop.”) After
watching the videos, facilitate a class discussion about the importance of
understanding fire behavior using the following questions:
 How can recognizing potential hazards completely change a
firefighter’s plan of action?
 What are the possible consequences of failing to recognize changes
in fire behavior?
 What is the point of no return in a flashover?
 How could recognizing rollover save lives?
Use the Discussion Rubric for assessment.
Key Points
I. Fire Development in a Compartment
A. Compartment – an enclosed room or space within a building
1. In an unconfined compartment, heat dissipates
2. In a confined compartment, heat is absorbed by the walls, ceiling,
floor, and other objects in the compartment
3. Heat transfer – raises the temperature of all the materials in the
compartment until they begin to pyrolize
a) Pyrolysis – the chemical decomposition of a substance through
the action of heat (IFSTA, 2008)
4. Ventilation-controlled – the term used to describe a fire when fire
development is limited by the air supply
B. Factors that affect fire development
1. Fuel type
2. Availability of an air supply
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3.
4.
5.
6.
7.
Availability and proximity of additional fuel
Compartment geometry (i.e. volume and ceiling height)
Ventilation and changes in ventilation
Thermal properties of the enclosure
Ambient conditions (e.g. wind, temperature, humidity, etc.)
II. Stages of Fire Development in a Compartment
A. Incipient Stage
1. Is the first stage of the burning process
2. Requires ignition – the moment when the three elements of the fire
triangle (fuel, air, and heat) come together and combustion occurs
a) Piloted ignition
b) Non-piloted ignition
c) Spontaneous ignition
3. Includes the following characteristics
a) The fire is small and confined to the initially ignited material
b) A plume of hot gases and flame rise from the fire and mix with
the cooler air within the room (convection)
c) As the plume reaches the ceiling, hot gases begin to spread
horizontally across the ceiling with a “mushrooming” effect
d) Hot gases that are in contact with the surfaces of the
compartment and its contents conduct heat to other materials
(conduction)
e) The fire has not yet influenced the environment to a significant
extent
4. Is when occupants can safely escape and the fire can be safely
extinguished with a portable extinguisher
5. Transitions to the growth stage at a rate dependent upon the type
and configuration of the fuel involved
B. Growth Stage
1. General Information
a) Is the early stage of a fire during which fuel and oxygen are
virtually unlimited
b) Includes the following characteristics
(1) A rapidly increasing release of heat
(2) The fire begins to influence the environment within the
compartment
(3) As the wall surfaces become hot, burning fuel receives
more reflected radiant heat (radiation), which further
increases the speed of fire development
2. Thermal layering
a) Heated gases tend to separate into layers according to
temperature
b) The difference in density between the hot smoke and the
cooler air causes them to separate into two distinct layers
(1) The hottest gases are found at the ceiling
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(2) The coolest gases are found at the floor
c) Synonymous terms
(1) Heat stratification
(2) Thermal balance
d) Firefighters want to maintain the level of the hot gas layer at
the ceiling or raise it above the floor in order to provide a more
tenable environment for themselves and trapped occupants
e) This action requires the effective application of fire control and
ventilation tactics
3. Isolated flames
a) Pockets of flames may be observed moving through the hot
gas layer (ghosting)
b) Ghosting is
(1) Classified as a fire gas ignition
(2) May be an indicator of developing flashover conditions
4. Rollover
a) The condition when unburned fire gases accumulate at the top
of a compartment and ignite, propagating flames through the
hot gas layer or across the ceiling
(1) Superheated gases are pushed (under pressure) away
from the fire area into the uninvolved areas, where they
mix with oxygen
(2) When the gases reach their flammable range and
additional oxygen is supplied (e.g. by opening doors and/or
applying fog streams), they ignite and expand very rapidly
in a rolling action across the ceiling
(3) Generally a rollover precedes a flashover, but rollovers do
not always result in flashovers
b) Similarities with ghosting include that it is
(1) Classified as a fire gas ignition
(2) A significant indicator of an impending flashover
5. Flashover
a) The rapid transition between the growth stage and the fully
developed stage
b) The conditions in the compartment change very rapidly from
partial to full involvement
c) When a flashover occurs, burning gases push out of the
compartment’s openings at a substantial velocity
d) Indicators of flashover
(1) Smoke – the presence of hot gases overhead and the
lowering of the hot gas layer are key indicators for
firefighters within the compartment
(a) May or may not be visible from the exterior
(b) Remember, smoke is unburned fuel that is ready to
ignite
(2) Air flow – any air flow that moves toward the fire can result
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in flashover
(3) Heat – rapidly increasing temperature is frequently a late
indicator
(4) Flame – may or may not be visible
(5) Building type – is not an indicator, but building factors can
influence how quickly a fire will reach flashover
e) Flashover – when the temperature in a compartment results in
the simultaneous ignition of all of the combustible contents in
the space (IFSTA, 2008)
f) The temperature range is from 900°F to 1200°F
(1) Auto-ignition temperature of carbon monoxide (CO) is
1128°F
C. Fully Developed Stage
1. Is the stage of the burning process when energy release is at the
maximum rate and is limited only by the availability of fuel and
oxygen (IFSTA, 2008)
2. Includes the following characteristics
a) All of the combustible materials in the compartment are burning
b) The burning fuels in the compartment are releasing the
maximum amount of heat possible for the available fuel and
ventilation
c) The fire is considered ventilation-controlled because the heat
release is dependent upon the compartment’s openings
d) Hot unburned gases are likely to flow from the origin
compartment to the adjacent compartments or the exterior
D. Decay Stage
1. Consumption of fuel
a) A fire enters the decay phase when it consumes the fuel
available in the compartment and its rate of heat release
declines
(1) The fire’s classification changes from ventilation-controlled
to fuel-controlled
(2) Temperature in the compartment may remain high for a
significant amount of time
b) Flammable products of combustion that have accumulated can
be ignited and result in a smoke explosion
2. Limited Ventilation
a) Fire enters the decay stage due to a lack of oxygen
b) Heat release also declines
c) A continuing combustion reaction may maintain an extremely
high temperature within the compartment
d) A large volume of flammable products of combustion can
accumulate within the compartment
(1) They can ignite explosively when mixed with additional air,
which results in backdraft
3. Backdraft
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a) An instantaneous explosion or rapid burning of superheated
gases that occurs when oxygen is introduced into an oxygendepleted, confined space
b) The stalled combustion resumes with explosive force
c) Occurs during ventilation-controlled fires because of
(1) Inadequate or improper ventilation procedures
(2) An increase in ventilation
d) The mixture of flammable products can be well above their
flammable limits
e) High temperatures remain
f) The more confined the air/fuel mixture is, the more violent the
backdraft
g) Pre-backdraft indicators
(1) Low oxygen
(2) High heat
(3) Smoldering fire
(4) High fuel-vapor concentrations
h) Common indicators of the potential for a possible backdraft
(1) Confined or excessive heat in windowless buildings
(2) Inwardly drawn smoke (sucking phenomenon)
(3) Little or no visible flame
(4) Smoke leaving the building in puffs
(5) Black smoke becoming dense gray-yellow
(6) Pressurized smoke exiting small openings
(7) Smoke stained windows with heat-induced cracking of
glass
i) When potential backdraft conditions are encountered,
firefighters should delay entry until after action is taken to
change the conditions inside the building or compartment
(1) Gas cooling with hose streams
(2) Vertical ventilation
j) Effects of a backdraft can vary considerably depending on
several factors
(1) Volume of flammable products of combustion
(2) Degree of confinement
(3) The speed with which fuel and air are mixed
(4) Where ignition occurs
III. Fire Control Theory
A. Fire Control Theory – fire is controlled and extinguished by limiting or
interrupting one or more of the essential elements in the combustion
process (fire tetrahedron)
B. Temperature Reduction (heat)
1. Cooling with water
a) Is one of the most common methods
b) Requires decreasing the temperature of a fuel to a point where
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it stops producing enough vapor to burn
c) Is the most effective method available for the extinguishment of
smoldering fires
d) Can extinguish fires with solid or liquid fuels that have high
flash points
e) Requires the application of enough water to absorb the heat
from the burning fuel
f) Cannot extinguish fires involving flammable liquids and gases
that have low flash points
2. Water’s greatest effect occurs when it is vaporized into steam; at
212°F it expands approximately 1700 times
a) Excess steam production can
(1) Make it difficult to see
(2) Can increase the chances for steam burns
b) It is important to control steam production through
(1) Using good nozzle techniques
(2) Using an appropriate volume of water
(3) Applying the water in the most effective form based on the
existing conditions
(a) Fog stream
(b) Straight stream
(c) Solid stream
C. Fuel Removal (fuel)
1. Any fire can be effectively extinguished by removing its fuel source
2. The most simple fuel removal method is allowing the fire to burn
until all of the fuel is consumed, which is appropriate in some
situations, such as
a) Fires involving pesticides
b) Flammable liquid spills
(1) Extinguishing with water creates substantial runoff, which
may be more harmful to the environment
(2) Allowing the fire to burn minimizes groundwater pollution
3. Fuel may also be removed by
a) Stopping the flow of liquid or gaseous fuel by closing a valve
(i.e. the preferred method of extinguishing pressurized gas
fires)
b) Removing solid fuels in the path of a fire
D. Oxygen Exclusion (oxygen)
1. Is the process of reducing the oxygen available during the
combustion process (e.g. using a cover to extinguish a grease fire
in a pan on a range-top)
a) Reduces a fire’s growth
b) May completely extinguish a fire if given sufficient time
2. Carbon dioxide
a) Displaces oxygen
b) Disrupts the combustion process
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3. Foam
a) Blankets the fuel to separate it from oxygen
b) Will not work on the rare fuels that are self-oxidizing
4. Closing a door to the fire room before leaving the building
a) Limits the air supply to the fire
b) Can sometimes prevent flashover
c) Can limit fire growth
E. Chemical Flame Inhibition (chemical chain reaction)
1. Extinguishing agents
a) Interrupt the combustion reaction
b) Stop flame production
c) Include the following examples
(1) Dry chemicals
(2) Halogenated agents (halons)
(3) Halon-replacement agents
d) Are effective on gas and liquid fuels because they must flame
in order to burn
e) Do not easily extinguish surface-mode fires because they work
on the chemical chain reaction of flaming combustion
f) Are not practical to use on smoldering fires due to very high
agent concentrations and the extended amount of time needed
for their extinguishment
Activities
1. Fire Behavior Assessment – Before class, research, review, and select
several firefighting videos of fires (house and/or training exercises). Have
the students watch the videos and assess the fires, describing the stages
of the fire and other fire behaviors (e.g. backdraft, rollover, and
flashover). Ask the students to identify safety issues that firefighters may
be overlooking (e.g. not wearing PPE or SCBA while in dangerous areas;
ladders raised above doors or windows). This activity can be a writing
activity or a class discussion. Scaffold the discussion or writing as
needed. Use the Discussion Rubric or the Individual Work Rubric for
assessment.
2. Checking a Door for Heat – Demonstrate how to properly check a door
for heat. Then have the students perform the skill while donning PPE.
Use the Fire Behavior Skill Rubric: Checking a Door for Heat for
assessment.
3. Checking for Heat Level in a Room – Demonstrate how to properly check
for the heat level in a room. Then have the students perform the skill
while donning PPE. Use the Fire Behavior Skill Rubric: Checking for Heat
Level in a Room for assessment.
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Assessments
Fire Behavior Quiz and Key
Fire Behavior Key Terms Quiz and Key
Fire Behavior Skill Rubric: Checking a Door for Heat
Fire Behavior Skill Rubric: Checking for Heat Level in a Room
Discussion Rubric
Individual Work Rubric
Presentation Rubric
Materials
Fire Behavior computer-based presentation
Computer with Internet access, projector, and screen
Computers with computer-based presentation software
One poster board (for two students) or card stock paper
Pencils, colors, markers, or other drawing materials
Personal protective equipment (PPE)
Resources
0135151112, Essentials of Firefighting (5th Edition), International Fire
Service Training Association (IFSTA), 2008.
Accommodations for Learning Differences
For reinforcement, students will draw a diagram of the stages of fire
development using half of a poster board (or card stock paper) and drawing
materials. The diagram should include arrows pointing to the locations where
rollover, flashover, and backdraft may occur. (Note: backdraft can occur at
any stage where heated gases are trapped and waiting for fresh air.) Use the
Individual Work Rubric for assessment.
For enrichment, students will create a computer-based presentation
explaining the visual indicators of a backdraft. Use the Presentation Rubric
for assessment.
State Education Standards
Texas Essential Knowledge and Skills for Career and Technical Education
§130.299. Firefighter I (One to Two Credits).
(5)
The student describes the stages of a fire, the process of
combustion, and the appropriate action to be taken for
extinguishment. The student is expected to:
(C)
describe the process of thermal layering that occurs in
structural fires and how to avoid disturbing the normal
layering of heat;
(F)
describe the hazards and the appropriate action to be
taken for extinguishment, including ignition, growth,
flashover, fully developed, and decay;
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College and Career Readiness Standards
Science Standards
I. Nature of Science: Scientific Ways of Learning and Thinking
A. Cognitive skills in science
1. Utilize skepticism, logic, and professional ethics in science.
2. Use creativity and insight to recognize and describe patterns
in natural phenomena.
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Fire Behavior Key Terms
Backdraft – instantaneous explosion or rapid burning caused by an increase in ventilation in an
oxygen-depleted confined space
Decay stage – the stage of fire development when energy release diminishes, temperatures
decrease, and fuel is consumed; the fire changes from ventilation-controlled to fuel
controlled
Deflagration – explosively rapid combustion
Flashover – the rapid transition between the growth stage and the fully developed stage that is
characterized by burning gases pushing out of the compartment’s openings at a
substantial velocity
Fully developed stage – the stage of fire development when energy release is limited only by the
availability of fuel and oxygen, and is at its maximum rate
Growth stage – the early stage of a fire during which fuel and oxygen are almost unlimited and
the release of heat increases rapidly
Ignition – the moment when the three elements of the fire triangle (fuel, air, and heat) come
together and combustion occurs
Incipient stage – the first stage of fire development, which includes ignition and isolated heat
production; the oxygen content of the air is not significantly reduced in this phase
Mushroom – when fire spreads horizontally through the compartment
Non-piloted ignition – occurs when a material reaches its autoignition temperature as the result
of self-heating (i.e. spontaneous ignition)
Piloted ignition – caused by a flame or spark
Rollover – the condition when unburned fire gases accumulate at the top of a compartment and
ignite, propagating flames through the hot gas layer or across the ceiling
Thermal layering – the tendency of gases to form layers according to temperature (hottest
gases at the ceiling and lowest gases at the floor) as a result of combustion in a confined
space
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Name ___________________________________Date __________________________
Fire Behavior Key Terms Quiz
Directions: Match the term with the correct definition.
1. _____Backdraft
7.
_____Fully developed stage
2. _____Incipient stage
8.
_____Mushroom
3. _____Non-piloted ignition
9.
_____Thermal layering
4. _____Flashover
10. _____Growth stage
5. _____Ignition
11. _____Decay stage
6. _____Rollover
12. _____Deflagration
*************************************************************************************************************
A. Instantaneous explosion or rapid burning caused by an increase in ventilation in an
oxygen-depleted confined space
B. The stage of fire development when energy release diminishes, temperatures decrease,
and fuel is consumed; the fire changes from ventilation-controlled to fuel controlled
C. Explosively rapid combustion
D. The rapid transition between the growth stage and the fully developed stage that is
characterized by burning gases pushing out of the compartment’s openings at a
substantial velocity
E. The stage of fire development when energy release is limited only by the availability of
fuel and oxygen, and is at its maximum rate
F. The early stage of a fire during which fuel and oxygen are almost unlimited and the
release of heat increases rapidly
G. The moment when the three elements of the fire triangle (fuel, air, and heat) come
together and combustion occurs
H. The first stage of fire development, which includes ignition and isolated heat production;
the oxygen content of the air is not significantly reduced in this phase
I. When fire spreads horizontally through the compartment
J. Occurs when a material reaches its autoignition temperature as the result of self-heating
(i.e. spontaneous ignition)
K. The condition when unburned fire gases accumulate at the top of a compartment and
ignite, propagating flames through the hot gas layer or across the ceiling
L. The tendency of gases to form layers according to temperature (hottest gases at the
ceiling and lowest gases at the floor) as a result of combustion in a confined space
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Fire Behavior Key Terms Quiz Key
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
A
H
J
D
G
K
E
I
L
F
B
C
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Name ___________________________________Date _________________________
Fire Behavior Quiz
1. _____Which of the following is a flashover indicator?
A. Puffing smoke
B. Air flow
C. Gray smoke
D. Rattling windows
2. _____Which of the following is NOT a flashover indicator?
A. Smoke
B. Heat
C. Vapors
D. Flame
3. _____When watching for a flashover, which of the following is unburned fuel that is ready
to ignite?
A. Smoke
B. Plastic
C. Wood
D. Paper
4. _____Which of the following is a true statement about “ghosting”?
A. It is classified as a fire gas ignition
B. It may be an indicator of developing flashover conditions
C. Both A and B
D. Neither A nor B
5. _____Which of the following is a deflagration caused by an increase in ventilation?
A. Flashover
B. Backdraft
C. Flameover
D. Rollover
6. _____Which of the following is NOT a condition that exists in pre-backdraft conditions?
A. Low Oxygen concentration
B. High heat
C. Smoldering fire
D. Fire venting through the roof
7. _____Which of the following are visual indicators of a backdraft?
A. Little or no visible smoke
B. Inwardly drawn smoke
C. Smoke stained windows
D. All of the above
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8. _____Which of the following is NOT a visual indicator of a backdraft?
A. Pressurized smoke exiting a small opening
B. Smoke leaving the building in puffs
C. Flames rolling from windows
D. Black smoke becoming dense
9. _____A backdraft will always occur immediately or soon after making an opening into the
involved building or compartment.
A. True
B. False
10. _____Which of the following is the first stage of fire development?
A. Decay stage
B. Incipient stage
C. Growth stage
D. Fully developed stage
11. _____Which of the following is the second stage of fire development?
A. Decay stage
B. Incipient stage
C. Growth stage
D. Fully developed stage
12. _____Which of the following is the third stage of fire development?
A. Decay stage
B. Incipient stage
C. Growth stage
D. Fully developed stage
13. _____Which of the following is the fourth stage of fire development?
A. Decay stage
B. Incipient stage
C. Growth stage
D. Fully developed stage
14. _____In which stage of fire development does thermal layering, rollover, and flashover
occur?
A. Decay stage
B. Incipient stage
C. Growth stage
D. Fully developed stage
15. _____Which of the following methods do firefighters use to influence fire behavior?
A. Reduce temperature
B. Eliminate fuel
C. Change the oxygen concentration
D. Interrupt the self-sustained chemical chain reaction
E. All of the above
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Fire Behavior Quiz Key
1. B
2. C
3. A
4. C
5. B
6. D
7. D
8. C
9. B
10. B
11. C
12. D
13. A
14. C
15. E
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Name _________________________________________ Date ___________________
Fire Behavior Skill Rubric:
Checking a Door for Heat
Skill: Checking a Door for Heat
20 pts. each
Dons personal protective equipment (PPE) correctly
Kneels on the same side as the door knob
Lowers his or her glove slightly and checks the temperature of the
door by touching the door with the back of his or her hand
Opens the door and removes his or her hand quickly
Remains in a low position away from the door
Total points (100 pts. possible)
Comments:
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Name _________________________________________ Date ___________________
Fire Behavior Skill Rubric:
Checking for Heat Level in a Room
Skill: Checking for Heat Level in a Room
20 pts. each
Dons personal protective equipment (PPE) correctly
Moves into a kneeling position
Feels for ambient heat by slightly removing his or her glove and
raising his or her arm above head level
Verbalizes the temperature of the conditions (e.g. the area is cool,
warm, or hot)
Remains in a low position (if the instructor says that the area is hot,
he or she exits quickly)
Total points (100 pts. possible)
Comments:
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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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Name:____________________________________
Date:_____________________________
Presentation Rubric
4 pts.
Excellent
Objectives
3 pts.
Good
2 pts. Needs Some
Improvement
1 pt. Needs Much
Improvement
N/A
Pts.
Topic/Content
 Topic discussed completely and in-depth
 Includes properly cited sources (if used)
Creativity/Neatness
 Integrates a variety of multimedia effects to
create a professional presentation (transition
and graphics) or appropriate visual aid used
 Title slide, table of contents, bibliography are
included, using acceptable format
Mechanics
 Grammar, spelling, punctuation, and
capitalization are correct
 Image and font size are legible to the entire
audience
Oral Presentation
 Communicates with enthusiasm and eye
contact
 Voice delivery and projection are dynamic
and audible
Audience Interaction
 Presentation holds audience’s attention and
relates a clear message
 Clearly and effectively communicates the
content throughout the presentation
Total Points (20 pts.)
Comments:
20
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