FIRE BEHAVIOR

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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


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