3 Fire Behavior Flashcards
1
Q
The science of fire is an attempt to understand and control fire and involves both scientific and commonsense answers to the following questions
A
How does fire transform matter. How does fire spread
2
Q
When material burns a visible change occurs, generating what
A
Heat and light
3
Q
What occurs when a material or substance remains chemically the same but changes in size shape or appearance
A
A physical change
4
Q
What occurs when a substance changes from one type of matter into another.
A
Chemical change
5
Q
Reactions that absorb energy as they occur are called
A
Endothermic
6
Q
Reactions that give off energy as they occur are called
A
Exothermic
7
Q
Fire is what
A
And exothermic chemical reaction called combustion that releases energy in the form of heat and light
8
Q
If your potential energy is released during combustion and converted into what
A
Kinetic Energy
9
Q
Some solid fuels particularly those that are porous can char and undergo oxidation on the fuel surface. This oxidation is known as
A
Nonflaming or smoldering combustion
10
Q
The old combustion model composing of oxygen fuel and heat
A
Fire triangle
11
Q
The new fire behavior model which explains smoldering combustion comprising of heat fuel or reducing agent chemical change reaction and oxidizing agent
A
Fire tetrahedron
12
Q
The fire tetrahedron is comprised of four elements
A
Fuel. Auction. Heat. Self sustained chemical reaction
13
Q
The material or substance being oxidized or burned in the combustion process
A
Fuel, reducing agent
14
Q
In organic fuels such as hydrogen or magnesium do not contain what
A
Carbon
15
Q
Organic fuels contain what
A
Carbon
16
Q
Organic fuel can be for the divided into two categories
A
Hydrocarbon-based, cellulose based
17
Q
To key factors influencing the combustion process are
A
Physical state and its distribution or orientation
18
Q
Three physical states of matter which fuel may be found
A
Solid liquid or gas
19
Q
For flaming combustion to occur fuels must be in what state
A
Gaseous
20
Q
A fuel that has definite size and shape
A
Solid fuel
21
Q
A type of plastic that is not readily change its physical shape when exposed to heat
A
Thermosetting plastics
22
Q
When wood is first heated what is released as the wood dries
A
Water vapor
23
Q
As surface increases the more material is exposed to heat in this generates combustible pyrolysis products more quickly making the fuel easier to ignite is the explanation of what
A
Surface to mass ratio
24
Q
The distribution and orientation of a solid fuel, vertical/horizontal, relative to the source of heat also affects what
A
The way it burns
25
A state of fuel that has mass and volume but no definite shape
Liquid fuel
26
Gasoline has a specific gravity of what
Less than one
27
Liquid fuels have a number of characteristics that contribute to their abilities to ignite and burn. These characteristics include the following
```
Solubility.
Vaporization.
Vapor pressure.
Flashpoint.
Flammable/combustible liquids.
Surface area
```
28
Flammable liquids have a flashpoint that is less than what temperature
Less than 100°F
29
Combustible liquids have a flashpoint that are greater than what temperature
Greater than 100°F
30
Transformation of a liquid to a vapor or gaseous state
Vaporization
31
Pressure produced or exerted by the vapor that a liquid releases. As a liquid is heated this increases along with the rate of vaporization
Vapor pressure
32
The temperature at which a liquid releases sufficient vapors to ignite but not sustain combustion, commonly indicate flammability hazard of liquid fuels
Flashpoint
33
Extent to which a substance will mix with water
Solubility
34
Substances that readily mix with water such as alcohol
Polar solvents
35
Materials that are miscible in water will mix in
Any proportion
36
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
37
The most dangerous type of all fuel types
Gaseous fuel
38
State of fuel that mass but no definitive shape or volume
Gaseous fuel
39
A gas that has a vapor density less than one and rises
Methane
40
Liquid petroleum gas tends to sink and has a vapor density less or greater than one
Greater than one
41
Vapor density is generally specified at what temperature
68°F
42
The primary oxidizing agent in most fires is what
Oxygen
43
At normal ambient temperatures materials can ignite and burn at oxygen concentrations as low as what percent
14%
44
Some petroleum-based materials will auto ignite during what condition
Oxygen concentrations are higher than 21%
45
And industrial bleaching agent used to typically for paper manufacturing
Hydrogen peroxide
46
many materials that do not burn at normal oxygen levels and burn readily and what type Of atmosphere
Oxygen enriched
47
The fuel to air concentration range that supports combustion is called
The flammable range. Or explosive range
48
Lowest Limit at which a flammable gas or vapor will ignite
Lel
49
Upper limit at which flammable gas or vapor will ignite
UFL
50
True/false. Variations in temperature and pressure can cause the flammable range to vary considerably
True
51
Generally increases in temperature or pressure brought in the range of
Flammability
52
Decreases in temperature and pressure does not narrow the flammable range. True/false
False it does narrow it
53
Energy exists in two states
Potential and kinetic energy
54
Potential energy is
The energy possessed by an object that may be released in the future
55
The energy possessed by a moving object is
Kinetic energy
56
Form of energy associated with the motion of atoms or molecules and capable of being transmitted through solid and fluid media by conduction convection and radiation
Heat
57
Heat moves away from fuel that is burning toward what
Fuel that is not burning
58
Flammable Range of methane
5% through 15%
59
Flammable range of propane
2.1% -9.5%
60
Flammable range of carbon monoxide
12% -75%
61
Flammable range of gasoline
1.4% -7.4%
62
Flammable range of diesel
1.3% -6%
63
Flammable range of ethanol
3.3% -19%
64
Flammable range of methanol
6% -35.5%
65
There are two forms of ignition
Piloted ignition and autoignition
66
This type of ignition occurs when a mixture of fuel and oxygen encounters and external heat source with sufficient heat energy to start the combustion reaction
Piloted ignition
67
This type of ignition occurs without any external flame or spark to ignite fuel gases or vapors
Autoignition
68
Temperature to which the service of a substance must be heated for ignition and self sustained combustion to occur
Autoignition temperature
69
The autoignition temperature is always higher than what
The pilot ignition temperature
70
The most common type of ignition is
Piloted ignition
71
Heat energy usually comes from one or more of the following sources
Chemical. Mechanical. Electrical. Light. Nuclear. Sound
72
The most common sources of heat that results in the ignition of fuel
Chemical and electrical and mechanical energy
73
The most common source of heat in combustion reactions
Chemical heat energy
74
Oxidation almost always results in the production of what
Heat
75
Heating that occurs when a material increases in temperature without the addition of external heat
Self heating, or spontaneous heating
76
For spontaneous ignition to occur the following set of circumstances must be met
Insulate of property of material must be so that it cannot dissipate as fast as it is being generated.
Rate of the production great enough to raise temperature to ignition point.
Available air supply adequate to support combustion
77
Heat generated as electrical current passes through a conductor such as copper wire
Electrical heat energy
78
Electrical heating can occur in several ways including the following
Resistance heating.
Overcurrent or overload.
Arcing.
Sparking
79
Heat produced when electric current flows through a conductor
Resistance heating
80
Unintended resistance heating
Overcurrent or overload
81
High temperature luminesce electric discharge across a gap or through a medium such as charted insulation
Arcing
82
Form of heat energy generated by friction or compression
Mechanical heat energy
83
Movement that results in the generation of heat and or Sparks, created went to services move against each other
Heat of friction
84
Energy created when a gas is compressed
Heat of compression
85
In order for heats to be transferred from one object to another the two objects must be a different
Temperatures
86
The transfer of heat from object to object is measured as
Energy flow overtime
87
Transfer of heat within an object or to another object by direct contact, heat flow through and between solids
Conduction
88
The transfer of heat energy for my fluid, liquid or gas, to a solid surface
Convection
89
Transmission of energy as an electromagnetic wave such as lightwaves radio waves are x-rays without an intervening medium
Radiation
90
All matter having a temperature above what will radiate heat energy
Absolute zero
91
This type of he becomes the dominant Mode of heat transfer when a fire grows in size and he can have significant effect on the ignition of objects located some distance away
Radiant heat
92
A wide range of factors influence radiant heat transfer including the following
Distance from heat source.
Temperature difference between source and material heated.
Collar and reflective qualities of heat source and material heated
93
As temperature of the heat source increases the radiant energy increases by a factor of what
Increases by a factor to the fourth power
94
Materials that absorbs heat but do not participate actively in the combustion reaction
Passive agents
95
A passive agent that slows the absorption of heat energy in the ignition and combustion process
Fuel moisture
96
Insulating materials retard the transfer of heat primarily by what
Slowing conduction from one body to another
97
Type of heat transfer that is the cause of most exposure fires
Radiation
98
A fourth method for heat transfer that has historically been used by the fire service is actually a combination of conduction and radiation rather than an independent method of heat transfer
Direct flame contact
99
Free radicals combined with oxygen or with the elements that form the fuel material producing what
Intermediate combustion products, new substances
100
Free radicals
Atom or group of atoms that has at least one unpaired electron, unstable and reactive
101
Methane burns it creates what
Carbon and hydrogen
102
When methane burns it creates what
Carbon monoxide and formaldehyde
103
Surface combustion also involves oxidation at the surface of the actual material without initiation or continuation of the chemical change reaction found in what type of combustion
Flaming combustion
104
Surface or smoldering combustion cannot be extinguished by chemical inhibition because
There are no flames and related chemical change reaction
105
Halon agents extinguish fires by
Interrupting the chemical chain reaction
106
An aerosol comprised of fire gases paper and solid particles
Smoke
107
Carbon monoxide is the byproduct of
Incomplete combustion of organic materials
108
Most common products of combustion encountered in structure fires
Carbon monoxide
109
This is Produced in The combustion of materials containing nitrogen and a significant byproduct of the combustion of polyurethane foam
Hydrogen cyanide
110
Product of complete combustion of organic materials is non-toxic but is an asphyxiant by displacing oxygen
Carbon dioxide
111
This class of fire involves ordinary solid combustible materials such as would cloth paper rubber and plastics
Class a fires
112
This class of fire involves my flammable and combustible liquids and gases such as gasoline oil and alcohol
Class B fires
113
Class c fires involve what
Energize electrical equipment
114
Combustible metals such as aluminum magnesium potassium sodium titanium and zirconium form this class of fire
Class D
115
True/false. No single extinguishing agent effectively controls fires and all combustible metals
True
116
Class K fires involve
Oils and greases normally found in commercial kitchens using deep fryer's
117
A process caused by class K extinguishing agents turning fats and oils into a soapy foam that extinguishes a fire
Saponification
118
When sufficient oxygen is available for development is controlled by the characteristics and configuration of the fuel and is considered to be
Fuel controlled
119
When fire development is limited by the air supply the fire is set to be
Ventilation controlled
120
Four stages of fire development
Incipient. Growth. Fully developed. Decay
121
Ignition occurs when all three elements of the fire triangle come together and combustion happens true or false
true
122
Once combustion begins development of an incipient fire is largely dependent on the characteristics and configuration of
Fuel involved
123
To draw in and transport as solid particles or gas, by the flow of a fluid
Entrain
124
The ceiling Jet is otherwise known as
Mushrooming
125
First affect caused by the transition into the growth stage is the amount of air that is
Drawn into the plume
126
What determines the amount of air that is entrained and thus the amount of cooling that takes place
Location of fuel in relation to the compartment walls
127
Thermal layering, isolated flames, rollover, and flashover are all found during what stage of fire
Growth stage
128
Pocket flames that may be observed moving through the hot gas layer above the neutral plane is sometimes referred to as
Ghosting
129
The rapid transition between the girls and fully developed by her stages but not a specific event like ignition
Flashover
130
When the temperature in a compartment results in the simultaneous ignition of all the combustible contents in the space
Flashover
131
Flashover temperature is typically occur between what
Between 900°F and 1200°F
132
The temperatures associate with flashover is a range that usually correlates with the autoignition temperature of what, commonly produced gas
Carbon monoxide
133
To develop flashover conditions the fuel must have sufficient
Heat energy
134
A seal room might not provide enough what for a developing fire to reach flashover
Ventilation, oxygen
135
Measurement of the amount of heat released when a material burns as stated in kilowatts or BTU
Heat release rate
136
Most fires they grow beyond incipient stage become what controlled
Ventilation controlled
137
The compartment fire will Decay as the fuel is consumed or as the oxygen concentration
Falls to the point where Flaming combustion can no longer be supported
138
Instantaneous explosion or rapid burning of superheated gases that occurs when oxygen is introduced into a smoldering fire in a confined space
Backdraft
139
Flammable products of combustion can accumulate within the compartment and if with in the flammable range they can ignite resulting in
Smoke explosion
140
Ignition of accumulated flammable products of combustion
Smoke explosion
141
A Backdraft will occur if the accumulated products of combustion are at or above their
Ignition temperature
142
The following factors influence fire development with in a compartment
```
Fuel type.
Availability and location of additional fuel.
Compartment volume.
Ventilation.
Thermal properties of compartment.
Ambient conditions.
Effects of changing conditions.
```
143
In a compartment fire the most fundamental fuel characteristics influencing fire development are
Mass and surface area
144
A number of factors influence the availability and location of additional fuels including the following
```
Building configuration.
Contents of building.
Construction of the building.
Interior finish materials.
Fuel proximity and continuity.
Fire location
```
145
Amount of fuel present express quantitatively in terms of weight of fuel per unit area
Fuel load
146
All things being equal a fire and a large compartment will develop more slowly than one in
A small compartment due to greater volume of air and material that must be heated
147
Firefighters influence our behavior by doing one or more of the following actions
```
Reducing temperature.
Eliminating fuel.
Separating the fire from available fuel.
Changing oxygen concentration.
Interrupting chemical chain reaction
```
148
When water is converted into steam at 212°F expands approximately how many times
1700 times
149
Simplest method of fuel removal is
To allow the fire to burn until all fuel is consumed
150
For fires involving pesticides or flammable liquid spills what might be the most appropriate action to extinguish
Allowing fuel to burn out because of possible environmental harm from water run off
151
Example of oxygen exclusion to extinguish fire would be
Covering a cooking fire pan with a lid. Dry chemical extinguisher
152
Halogenated agents are effective in extinguishing gas and liquid fuels because
They interrupt chemical change reaction and the fuels must flame to burn
153
The primary duty of the fire inspector is to ensure
The life safety of all citizens and fire emergency services responders
