FVCC Fire Rescue
FIRE BEHAVIOR
OBJECTIVES
 2-2.1
 2-2.1.1
 2-2.1.2
 2-2.1.3
 2-2.1.4
 2-2.1.5
 2-2.1.6
Identify the following terms: (3-3.10)
Fire/combustion
Heat
Ignition temperature
Flammable limits/flammable range
Vapor density
Solubility
OBJECTIVES
 2-2.2
Identify the components of the fire triangle
and fire tetrahedron (3-3.10)
 2-2.3
Identify the relationship of the concentration
of oxygen to combustibility and life safety (3-3.1)
 2-2.4
Identify four products of combustion
commonly found in structural fires that create a life
hazard. (3-3.1)
 2-2.5
Identify the three methods of heat transfer
(3-3.9, 3-3.11)
OBJECTIVES
 2-2.6
Identify the Law of Heat Flow
 2-2.7
Identify the three physical states of matter in
which fuels are commonly found. (3-3.9)
 2-2.8
Identify the following conditions and explain
their associated hazards and appropriate actions: (3-3.10)
OBJECTIVES
 2-2.8.1
 2-2.8.2
 2-2.8.3
 2-2.8.4
 2-2.8.5
 2-2.8.6
 2-2.8.7
Ignition/Incipient
Growth/Freeburning
Rollover/Flameover
Flashover
Fully developed
Decay/Hot smoldering
Backdraft
OBJECTIVES
 2-2.9
Identify the process of thermal layering that
occurs in structural fires. (3-3.11)
 2-2.10
Identify how to avoid disturbing the normal
layering of heat.
o IFSTA, Essentials, 4th ed, Chapter 2
o Delmar, Firefighter’s Handbook, 2000, Chapter 4
FIRE TERMS
 Fire/combustion
 Fire: Self-sustaining process of rapid oxidation of a fuel which
produces heat and light
 Combustion: Self-sustaining chemical reaction yielding energy
or products that cause further reactions
 These terms are often used interchangeably; most often used in
fire
FIRE TERMS
 Heat
 The form of energy that raises temperature
 The energy transferred from one body to another when the
temperature of the bodies are different
 Can be measured by the amount of work it does
 Ignition temperature
 The minimum temperature to which a fuel, in air, must be
heated to start self-sustained combustion without a separate
ignition source.
FIRE TERMS
 Flammable Limits/flammable range
 Highest and lowest percentage of a flammable gas or vapor, in air, that
will explode or ignite
 Concentrations below the Lower Explosive (flammable) Limit are too
“lean” to burn
 Concentrations above the Upper Explosive (flammable) Limit are too
“rich” to burn
 Flammable (explosive) Range: The range between the Lower
Explosive (flammable) Limit and the Upper Explosive (flammable)
Limit
 The word explosive and flammable are often used interchangeably
FIRE TERMS
 Vapor density:
 Weight of a given volume of pure vapor or gas compared to the
weight of an equal volume of dry air at the same temperature
and pressure
 Vapor density less than one indicates a vapor lighter than air
 Vapor density greater than one indicates a vapor heavier than air
FIRE TERMS
 Solubility
 Degree to which a solid, liquid, or gas dissolves in a solvent
(usually water)
FIRE TRIANGLE & FIRE TETRAHEDRON
 Fire triangle – heat, fuel, oxygen
 Representative of surface combustion (smoldering fire)
 Fire tetrahedron
 Chemical chain reaction is added to the fire triangle
 Representative of the flaming mode of combustion
RELATIONSHIP OF OXYGEN TO LIFE
SAFETY
 Concentrations below twenty-one percent has some
effect on life safety
 At nine percent, an individual becomes unconscious
 At six percent, death will occur within a few minutes
 In concentrations below eighteen percent, fire begins to
decrease
 Generally concentrations below fifteen percent will not support
combustion
PRODUCTS OF COMBUSTION
 Heat
 Responsible for the spread of fire
 Cause of burns and other injuries
 Smoke
 Mixture of carbon particles and fire gases
 Makeup varies from fuel to fuel, all smoke is considered toxic
 The material burning has a direct influence on the amount and
color of smoke
PRODUCTS OF COMBUSTION
 Fire gases
 Carbon monoxide (CO)
 Carbon Dioxide (CO2)
 Hydrogen Cyanide
 Sulfur Dioxide
 Nitrogen
 Other gases depending on fuel being burned
PRODUCTS OF COMBUSTION
 Flame (light)
 More complete the combustion, less luminous the flame
 Flame absent in smoldering fire
HEAT TRANSFER
 Conduction
 Heat conducted from one body to another either by direct
contact or by an intervening heat conducting medium
 Depends on type of conductor: metal (good), drywall (poor)
 Example: Metal plumbing components or electrical conduit
HEAT TRANSFER
 Convection
 Transfer of heat energy by the movement of air or liquid
 Heated gases rise: mushrooming
 Examples: Fire traveling through elevator shafts, stairways,
balloon frame walls
 Direct flame contact is actually a form of convection heat
transfer
HEAT TRANSFER
 Radiation
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Transfer by heat waves
Travels through space until it reaches an opaque object
Light colors reflect radiant heat; dark colors absorb radiant heat
Major source of fire spread to exposures (important to protect
exposures from radiant heat)
LAW OF HEAT FLOW
 Heat flows from a hot substance to a cold substance
 A colder substance will absorb heat until temperatures are
equal
3 PHYSICAL STATES OF MATTER
 Solid fuels
 Have a definite shape and size
 Surface to mass ratio
 The more surface areas exposed – the less energy is required for ignition
 Pyrolysis
 The chemical decomposition of a substance through the action of heat
 The position of the fuel affects the way it burns
 A solid fuel in a vertical position will allow fire spread more rapidly than
the same fuel in a horizontal position
3 PHYSICAL STATES OF MATTER
 Liquid fuels
 Fuel gases are generated by a process called vaporization
 Vaporization: The transformation of a liquid to its vapor or gaseous state
 Energy input usually in the form of heat
 Requires less energy than said fuels
 With liquids, the surface to volume ratio is important
3 PHYSICAL STATES OF MATTER
 Gaseous fuels
 Can be the most dangerous of all fuel types because they are
already in the natural state required for ignition
 Must be mixed with air in the proper proportion to burn; i.e.
flammable range
PHASES OF FIRE
 Incipient/ignition 2-2.8.1
 Occurs when the four elements of the fire tetrahedron come together and
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combustion begins
Can be caused by a spark or flame
Can occur when a material reaches its ignition temperature through selfheating
Limited to original materials ignited
Small quantity of fire gases being generated
Flame temperature above 1000 degrees F. yet room temperature is only
slightly increased
Easiest to extinguish
PHASES OF FIRE
 Growth/freeburning 2-2.8.2
 Fire plume begins to form above the burning fuel
 Begins to draw air from the surrounding space into the plume
 Hot gases rise, hit the ceiling and spread until they reach the
walls
 As fire grows, the overall temperature increases
PHASES OF FIRE
 Rollover/flameover 2-2.8.3
 The ignition of combustible gases which have spread throughout
the fire area
 Differs from flashover in that only combustible gases are
burning
 One reason why firefighters stay low when entering a burning
building
 Controlled by extinguishing main body of fire
 Flame spread movement of flame away from source of ignition
PHASES OF FIRE
 Flashover
 Transition between the growth stage and fully developed stage of a
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compartment fire
Occurs when flames flash over the entire surface of a room
Occurs as a result of all the materials in the room reaching their
ignition temperatures
Involves all exposed combustible surfaces in the compartment
Temperatures range from 900 degrees F-1200 degrees F.
Survivability unlikely if caught in a flashover
PHASES OF FIRE
 Fully developed
 All combustible materials in the compartment are involved
 Releasing the maximum amount of heat and producing large
amounts of fire gases
 Hot unburned gases are flowing from the compartment and
igniting when they enter a space with abundant air
PHASES OF FIRE
 Decay/Hot smoldering fire 2-2.8.6
 As fuel is consumed, the rate of heat decreases
 Amount of fire diminishes and temperature begins to decline
 Glowing embers can maintain moderately high temperatures
PHASES OF FIRE
 Backdraft (smoke explosion)
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Explosion or rapid burning of heated gases
Occurs when oxygen is introduced into a smoldering fire
Often caused by improper ventilation
Warning signs:
 Pressurized smoke exiting small openings
 Dense gray-yellow smoke
 Confinement and excessive heat
 Little or no visible flame
 Smoke leaving building in “puffs” (smoke puffing out and then sucking back in)
 Smoke stained windows
 Muffled sounds
PHASES OF FIRE
 Backdraft cont.
 Warning signs
 Sudden rapid inward movement of air when an opening is made
 Situation can be made less dangerous by proper ventilation. Open at
highest point involved. Heated smoke and gases will be released,
reducing the possibility of an explosion
THERMAL LAYERING
 The tendency of gases to form into layers according to
temperatures
 Sometimes referred to as heat stratification or heat balance
 Hottest gases tend to be at the ceiling and cooler gases towards
the floor
 Thermal layering is critical to firefighting operations
HOW TO AVOID DISTURBING THE
THERMAL LAYERING
 Thermal layering can be disrupted if water is applied directly
into the layer without proper ventilation
 Results in higher temperatures at the floor level and decreased
visibility.
 Firefighters may suffer steam burns if thermal layering is
disrupted
Homework
 Match types and states of energy to their definitions. Write the correct letters on the
blanks.
 _____ 1. Energy developed when electrons flow through a
conductor
 _____ 2. Energy possessed by a moving object
 _____ 3. Energy released when atoms are split
 _____ 4. Visible radiation produced at the atomic level
 _____ 5. Energy an object possesses that can be released in the
future
A. Mechanical energy
D. Light
B. Fusion
C. Potential energy
E. Electrical energy
Homework
 Match heat and temperature terms to their definitions. Write the correct letters
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on the blanks.
_____ 6. The amount of heat required to raise the temperature of 1 pound of
water 1 degree Fahrenheit
_____ 7. The amount of work done by a force of 1 newton through a distance of 1
meter
_____ 8. The relationship between the calorie and the joule
_____ 9. The amount of heat required to raise the temperature of 1 gram of
water 1 degree Celsius
_____ 10. The unit of temperature measurement in the customary system
A. Degrees Fahrenheit B. Mechanical equivalent of heat
C. Joule
D. British thermal unit
E. Calorie
Homework
 Distinguish among the three methods of heat transfer. Mark “A” for examples of
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conduction, “B” for examples of convection, and “C” for examples of radiation.
A = Conduction B = Convection C = Radiation
_____ 11. A basement fire heats pipes enough to ignite the wood inside walls
several rooms away.
_____ 12. Fire spreads from the first to the third floor up a stairwell.
_____ 13. The heat from a burning building ignites a second building 20 feet
away.
_____ 14. Hot water heats a radiator.
_____ 15. A firefighter testing hose on the ramp receives a sunburn.
_____ 16. The ventilation team opens the roof of a burning building and smoke
and flames issue from the opening.
Homework
 Match properties of matter to their definitions. Write the correct letters on the blanks.
 _____ 17. Mass, size, or volume
 _____ 18. How tightly the molecules of a solid substance are packed together
 _____ 19. Solid, liquid, or gas
 _____ 20. The density of a gas in relation to air
 _____ 21. The ratio of the mass of a given volume of liquid to the mass of an equal
volume of water
a. Density
b. Specific gravity
d. Physical state
c. Physical property
e. Vapor density
 Identify chemical reactions. Match the name of the described chemical reaction the letter
provided.
___ 22. The formation of a chemical bond between oxygen and another element
___ 23. Alters the chemical makeup of a substance
___ 24 . Does not alter the chemical makeup of a substance
___ 25. Gives off energy as it occurs
___ 26. Absorbs energy as it occurs
A. Physical change B. Chemical change C. Exothermic reaction
D. Endothermic reaction E. Oxidation
Homework
Match the name of the described types of oxidation the letter
provided
___ 27. Rapid oxidation
___ 28. Slow oxidation
___ 29. Instantaneous oxidation
a) Explosion
b) Fire
c) Rust
HOMEWORK
A.Fuel
B.Oxygen
C.Chemical
Reaction
D.Heat
30. ____
32. ____
31. ____
33. ____
Homework
 Select facts about oxidizing agents. Write the appropriate letters on the blanks.
___ 34. Which of the following is not a likely characteristic of an oxygen-enriched
atmosphere?
 a. Materials burn more rapidly
 b. Ignition requires higher temperatures
 c. Some petroleum-based materials will autoignite
 d. Some materials will burn vigorously even though they do not burn at normal oxygen
levels
___ 35. Which of the following fuels could burn in an oxygen-free atmosphere?
 a. Methane b. Hydrocarbon liquid c. Alcohol d. Sodium nitrate
___ 36. Oxygen concentrations as low as ___ percent can support combustion at room
temperature.
 a.
21
b.
19
c. 18
d. 14
___ 37. What percent oxygen does atmospheric air normally contain?
 a.
17
b. 21
c. 28
d. 12
Homework
 Identify a each false statement and mark with letter “B” and each true statement with the
letter “A”.
___ 38. The shape and size of a fuel affects its ignitability.
___ 39. As a fuel's surface-to-mass ratio decreases, its ignitability
increases.
___ 40. When a solid fuel is in a vertical position, fire spread is more
rapid than when it is in a horizontal position.
___ 41. Liquid fuels have physical properties that increase the
difficulty of extinguishment and the hazard to personnel.
___ 42. Volatility is the ease with which a liquid gives off vapor.
___ 43. Flammable limits — how rich or how lean the fuel vapor can
be and still burn — are recorded in handbooks and are
usually reported at ambient temperatures and atmospheric
pressures.
Homework
 Identify stages of compartment fire development. Match the name of the stage described
in the blank provided.
___ 44. The fire becomes fuel controlled, the amount of fire diminishes, and temperatures
within the compartment begin to decline.
___ 45. The combustible materials in the compartment and the gases given off by pyrolysis
ignite.
___ 46. Rising hot gases hit the ceiling and spread outward until they hit the compartment
walls; the depth of the gas layer begins to increase and causes radiant heating of
combustible materials.
___ 47. The four elements of the combustion tetrahedron come together; can be piloted or
non-piloted.
___ 48. All combustible materials in the compartment are involved in fire, releasing the
maximum amount of heat possible and producing large volumes of fire gases.
a. Ignition b. growth c. flashover d. fully developed e. decay
Homework
Select facts about the products of combustion. Write the appropriate letters on the blanks.
___ 49. Which of the following does not happen to a fuel when it burns during incomplete
combustion?
A. It undergoes a chemical change B. It releases gases and liquids
C. The elements making up the fuel are destroyed
D. Some of it is converted to energy
___ 50. Which of the following products of combustion would not be present in a smoldering fire?
 a. Fire gases
b. Smoke
c. Heat
d. Flame
___ 51. What happens to the flame as combustion becomes more complete?
 a. It becomes cooler and less luminous
 b. It becomes cooler and more luminous
 c. It becomes hotter and less luminous
 d. It becomes hotter and more luminous
___ 52. What is the most common of the hazardous substances contained in smoke?
a. Carbon monoxide b. Chlorine c. Hydrogen cyanide
4. Carbon dioxide
___ 53. What causes the most deaths in fires?
a. Radiant heat
b. Smoke
c. Contact with heat conductive surfaces d. Direct flame contact
Homework
 Select facts about fire extinguishment theory. (1 pt. each, 4/5)
54. What type of extinguishment theory does flooding an area with carbon dioxide illustrate?
a. Fuel removal b. Chemical flame inhibition c. Oxygen dilution d. Temperature reduction
55. Which of the following illustrates extinguishment by fuel removal?
a. Flooding an area with an inert gas b. Establishing a negative heat balance
c. Blanketing with foam
d. Allowing the fire to burn until all fuel is consumed
56. Which of the following is an example of an extinguishing agent used to interrupt the
chemical chain reaction and stop flaming?
a. Carbon dioxide b. Halon
c. Water
d. Class A foam
57. Which of the following fuels cannot be easily extinguished through chemical flame
inhibition?
a. Low flash point liquids and flammable gases b. Solid flaming fuels
c. High flash point liquids
d. Solid smoldering fuels
58. Which of the following is a polar solvent?
a. Alcohol b. Gasoline
c. Petroleum jelly d. Motor oil
Homework
 Match fire classes to their descriptions. Write the correct
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letters on the blanks.
_____ 59. Energized electrical equipment
_____ 60. Ordinary combustibles
_____ 61. Flammable and combustible liquids and gases
_____ 62. Combustible metals
A. Class A
B. Class B
C. Class C
D. Class D
Homework
 Match fire classes to their primary extinguishment methods. Write
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the correct numbers on the blanks.
_____ 63. The application of non-conducting extinguishing agents
such as halon, dry chemicals, or carbon dioxide
_____ 64. Blanketing and smothering with fuel-specific
extinguishing agents (usually dry powder agents)
_____ 65. Cooling or quenching with water or “wet water” foams
_____ 66. Smothering, blanketing, or oxygen exclusion
with various extinguishing agents
A. Class A B. Class B C. Class C D. Class D