FIRE BEHAVIOR
what is a british thermal unit (BTU)
the amount of heat needed to raise the temperature of one pound of water one degree fahrenheit
what is the neutral plane?
the interface between the hot and cool gas layers in a compartment
which is the best definition of fuel load?
the total quantity of combustible contents of a building, space or fire area
how do dry chemical agents extinguish fires?
they disrupt the chemical chain reaction
which statement about flammable liquid is most correct?
they will not burn unless vaporized
which property tells you if a gas will collect at ground level?
vapor density
what is the process by which a liquid changes into a gas?
vaporization
a fire with limited air supply is a ... fire
ventilation-controlled
on the celsius scale, at what temperature does water begin to boil?
100
a combustible liquid has a flash point higher than ...
100 deg F
a flammable liquid has a flash point less than ...
100 deg F
at which ceiling temperature does flashover usually occur?
1100 deg F
if one cubic foot of water is completely vaporized, how many cubic feet of steam will be produced?
1700
OSHA defines oxygen deficiency as a percentage of oxygen in air less than ... %
19.5
what is the normal percentage of oxygen in the atmosphere?
21
on the fahrenheit scale, at what temperature does water begin to boil?
212
an oxygen enriched atmosphere is defined by OSHA as a percentage of oxygen in air greater than ...%
23.5
what is the amount of heat required to raise one pound of water one degree fahrenheit called?
BTU
a fire occurring in an enclosed space is a ... fire
compartment
what is heat transfer between bodies through direct contact?
conduction
fire spreads upward within a building due to rising superheated air. which means of heat transmission is this?
convection
what is transfer of heat by movement of a fluid?
convection
which material conducts heat most readily?
copper
all combustible materials in a compartment are involved in fire. this describes which phase of fire development?
fully developed
during which phase of development is a fire most likely to become ventilation-controlled?
fully developed
which is one of the phases of fire development?
fully developed
which product has the lowest flash point?
gasoline
flashover typically occurs during which phase of fire?
growth
what is the second stage of fire development?
growth
which is one of the phases of fire development?
growth
which is the energy component of the fire tetrahedron?
heat
which one of these statements about heat transfer is correct?
heat moves from a warmer object to a cooler one
as a fuel burns, the amount of heat released over a period of time is the ...
heat release rate
a bearing overheats in a motor causing ignition of nearby combustibles. this is an example of ignition by ... heat energy
mechanical
heat of compression is an example of which type of heat energy?
mechanical
heat of friction is an example of which type of heat energy?
mechanical
what is a more traditional term for a ceiling jet?
mushrooming
all of the following are methods of extinguishing fire except one.
neutralizing the catalyst
what is a chemical reaction between oxygen and another substance?
oxidation
what are materials that are not themselves combustible but support combustion?
oxidizers
which is one of the components of the fire tetrahedron>
oxidizing agent
extinguishing fire with a foam blanket is an example of which method of extinguishment?
oxygen exclusion
extinguishing fire with an inert gas is an example of which method of extinguishment?
oxygen exclusion
anything that occupies space and has mass is ...
matter
on the celsius scale, at what temperature does water begin to freeze?
0
on the fahrenheit scale, at what temperature does water begin to freeze?
32
what is a ceiling jet?
a layer of hot gases spreading horizontally as the plume contacts the ceiling
a vapor concentration in air is too rich to burn. this concentration is ...
above the upper flammable limit
which liquid is miscible in water?
alcohol
what is the term for surrounding atmospheric conditions inside or outside a structure?
ambient
in order for heat to be transmitted from one body to another, the bodies must be ...
at different temperature
which term means the minimum temperature to which a specific fuel must be heated in order for self-sustained combustion to occur without an outside ignition source?
autoignition temperature
what is a process of rapid oxidation that produces heat and light?
combustion
dealing with an unventilated compartment fire is particularly risky because of the potential for ...
backdraft
what is likely to happen if fresh air is rapidly introduced into a ventilation-controlled compartment fire?
backdraft
what is indicated by a structure which appears to be "breathing" smoke?
backdraft conditions
a vapor concentration in air is too lean to burn. this concentration is ...
below the lower flammable limit
which odor is associated with hydrogen cyanide gas?
bitter almonds
in general, which is the most common toxic product of combustion found in structure fires?
carbon monoxide
which material has the widest flammable range?
carbon monoxide
self-heating is an example of ... heat energy
chemical
spontaneous ignition of a wad of linseed oil-soaked rags is caused by which form of heat energy?
chemical
what is the primary toxic effect of hydrogen cyanide?
chemical asphyxiant
which is one of the components of the fire tetrahedron?
chemical chain reaction
available fuel or oxygen is consumed and flaming combustion fire is diminishing. what phase of fire development does this describe?
decay
entraining air has what effect on the plume?
decreases temperature
what is the primary toxic effect of carbon monoxide?
decreases the blood's capacity to carry oxygen
which motor works on the principle of the heat compression?
diesel fuel piston
what is the primary toxic effect of carbon dioxide?
displaces oxygen from the air
excessive current flowing through a wire causes the insulation to ignite. this is an example of ignition by ... heat energy
electrical
a reaction that absorbs energy is ...
endothermic
the capacity to perform work is a definition of ...
energy
a reaction that releases energy is ...
exothermic
the minimum temperature at which a liquid gives off sufficient vapors to sustain combustion is its ...
fire point
what is the term for the concentration of fuel vapor in air that can be ignited?
flammable range
the minimum temperature at which a liquid gives off sufficient vapors to momentarily ignite if provided with an outside ignition source is its ...
flash point
what is the term for the rapid transition from the growth stage to the fully development stage?
flashover
liquids with a specific gravity of less than one will ... water
float on
which gas is a common product of combustion?
formaldehyde
allowing a fire to burn itself out is an example of which method of extinguishment?
fuel removal
a fire with limited fuel supply is a ... fire
fuel-controlled
which substance is associated with burning polyurethane foam?
hydrogen cyanide
a fire in which location has the highest plume temperature?
in the corner of a compartment
a fire in which location will spread the most rapidly?
in the corner of a room
what is the first stage of fire development?
incipient
which is the primary factor in the production of carbon monoxide?
incomplete combustion of organic materials
for a given mass of solid fuel, as surface area decreases, the energy required for ignition...
increases
how do halon-replacement agents extinguish fire?
inhibiting the chemical chain reaction
which statement about nomex is correct?
it may ignite and burn vigorously in an oxygen-enriched atmosphere
which statement about a polar solvent is correct?
it will mix with water
which is the unit of heat energy in SI?
joule
a moving object possesses what kind of energy?
kinetic
what is heat?
kinetic energy in the form of vibrating molecules
which one of these characteristics in a solid fuel will increase the rate of pyrolysis?
large surface area relative to mass
what is the specific gravity of most flammable liquids?
less than 1
pyrolysis of wood begins at approximately which temperature?
less than 400 deg F
which is the best indicator of impending flashover?
lowering of the hot gas layer
which item has the highest heat release rate?
polyurethane foam mattress
which is a sign of potential backdraft?
pulsing, puffing discharges of smoke
heat causes combustible vapors to evolve from a solid fuel in which process?
pyrolysis
heat transmitted by ... travels in a straight line and at the speed of light
radiation
which form of heat transfer causes most exposure fires?
radiation
which type of heat transmission occurs via electromagnetic waves?
radiation
fuel in the combustion process is the ...
reducing agent
fighting fire with water is an example of which method of extinguishment?
reducing temperature
if a gas has a vapor density of less than one, it will ...
rise and dissipate
what is the term for the ignition of unburned gases in the hot gas layer at the top of a compartment?
rollover
which property tells you if a liquid will float on water?
specific gravity
what is required in order for spontaneous ignition to occur?
sufficient insulation to prevent heat dissipation
which is the most significant class A fuel characteristic influencing fire behavior in a compartment?
surface-to-mass ratio
what does the term thermal layering refer to?
tendency of gases to form layers according to temperature
