Chapter 5-Fire Behavior

the study of the physical world around us that includes the sciences of chemistry and physicals is called

physical science

energy exists in which of the following states

kinetic and potential energy

___is a rapid and self sustaining chemical process that yields heat and usually light

fire and oxidation

our atmosphere contains___oxygen

21%

chemical reactions in which a substance absorbs heat energy are called

exothermic heat reactions

chemical reactions between two or more materials that changes the materials and produces heat, flames, and toxic smoke are

exothermic heat reactions

oxidation reactions can be characterized by which of the following

exothermic and energy releasing

the four main components of the fire tetrahedron include fuel, heat, oxygen and

self sustained chemical reaction

which of the following statements regarding the fire tetrahedron is not true

the fire triangle has always been a more accurate representation of combustion , than the fire tetrahedron

an oxidizer would be defined as

a material that yields oxygen or other oxidizing gases during the course of a chemical reaction

what is a measurement of kinetic energy

temperature

which statement is true

heat energy will move from objects of higher temperature to those of lower temperature

in the SI system the unit for work is

joule

a joule is equal to

1 newton over the distance of 1 meter

____is a form of energy characterized by vibration of molecules and capable of integrating in supporting chemical changes and changes of state

heat

water will be in a frozen state at which of the following temperatures

0 degrees, 0 degrees, 32 degrees

water will boil at which of the followign temperatures

202 and 100 degrees

the temperature scale in which water freezes at 0 and boils at 100 is known as

celsius

the amount of heat necessary to raise one gram of water 1 degree celsius is known as a

calorie

how many joules of heat energy must be added to a kilogram of water in order to increase its temperature by 1 degree Celsius

4200

the chemical decomposition of a substance through the action of heat is called

pyrolysis

which of the following would be considered forms of ignition

autoignition and piloted ignition

which type of ignition occurs when a mixture of fuel and oxygen encounter an external heat source with sufficient heat energy to start the combustion reaction

piloted ignition

___occurs without any external flame or spark to ignite the fuel gasses or vapors

autoignition

the lowest temperature at which a combustible material ignites in the air without a spark or flame is known as the

autoignition temperature

which would not be considered common sources of heat that result in ignition of fuel

light energy

which is the most common source of heat in combustion reactions

chemical energy

a form of chemical heat energy that occurs when a material increases in temperature without the addition of external heat is called

self heating and spontaneous ignition

for spontaneous ignition to occur, all but which of the following factors are required

the rate of heat production must be proportional to the amount of fuel present

the measure of a materials ability to transfer heat energy to other objects is known as

temperature

resistance heating, overcorrect, arcing, and sparking are all examples of which type of heating

electrical heating

a high temperature luminous electrical discharge across a gap through a medium such as charred insulation would be considered

arching

the heat that is produced when electrical current flows through a conductor is called

resistance heating

the heat that is produced when electrical current flows through a conductor is called

resistance heating

luminous particles formed and spattered away from a point of arching is refereed to as

sparking

when a current flowing through a conductor exceeds its design limits, it may overheat and present an ignition hazard. this type of heat is called

over-current or overload

all of the following materials would be considered spontaneous heating materials except

spandex and other synthetic cloths

the heat energy that is generated by friction or compression is called

mechanical heat energy

the movement of two surfaces against each other creates

heat of friction

___is generated when a gas is compressed

heat of compression

which statement regarding heat is NOT true

the greater the temperature difference between two bodies, the lesser the transfer rate of heat will be

physical flow or transfer of heat energy can be transefered from one body to another by direct contact of the two bodies, or by an inventing heat conduction medium. this would be known as-

conduction

of all the choices below, which is the best conductor of heat

metals

The transfer of heat is true eat by movement of heated fluids or gases, usually is an upward direction is known as

convection

which statement regarding heat transfer is true

the flow of heat is from the warmer area to the cooler area

heat generated from the sun in the form of waves would be known as

radiation

you are in the basement of a building , the fire has heated up a pipe to such a high temperature that it has ignited a floor joist several yards away. this type of heat transfer would be known as

conduction

there is a fire on the lower floor of a stairwell. the temperature in the stairwell increases to a level where the ceiling ignites several floors up. this is an example of

convection

there is a fully involved structure fire in a residential neighborhood. the houses are so close together what there is a serious exposure problem. what form of heat transfer creates the greatest risk to the exposed structures

radiation

the radiation of heat is the transmission of energy as an electromagnetic wave, without an intervening medium. which of the following would also be considered examples of electromagnetic waves

light waves, radio waves, and xrays

which of the following forms of matter will burn

gasses

the weight of a given volume of purevapor or gas compared to the weight of an equal volume of dry air at the same temperature and pressure is known as

vapor density

most gases are heavier than air, however there are exceptions which of the following gases has a vapor density which makes it lighter than air

methane

the ratio of the mass of a given volume of a liquid compared to its mass of an equal volume of water at the same temperature is called

specific gravity

the specific gravity of water equals

1

substances with a specific gravity grater than water will be

heavier than water and will have a value greater than 1

the transformation of a liquid to vapor or gaseous state is known as

vaporization

the pressure produced or exerted by vapors released by a liquid is known as

vapor pressure

the minimum temperature at which a liquid gives off enough vapors to form an ignitable mixture with air near a liquieds surface is called its

flash point

the minimum temperature at which a liquid produces sufficient vapors to support combustion once the fuel is ignited is called its

fire point

most ignitable liquids

have a specific gravity less than one

which would be considered a polar solvent

ethanol

when considering solubility of a liquid fuel, which of the following would you expect to dissolve in water

polar solvents

the degree to which a solid, liquid, or gas dissolves in a solvent is known as its

solubility

___describes materials that are capable of being mixed

miscible

the chemical decomposition of a substance through the action of heat is known as

pyrolysis

the size of solid fuels significantly effects the ignitablity of the fuel. In view of this, which of the following statements is true regarding as a solid fuels surface to mass ratio

as the surface area increases the ignitability increases

the physical position of a fuel plays a role in the rate of pr. Fire will spread more rapidly when a solid fuel is in a ___position because of

vertical/ conduction

for wood, when does pyrolysis begin

at temperatures below 400 degrees F

at which state of pyrolysis will the majority of moisture already have been releases and charring has begun

stage 2

at which stage of pyrolysis will free burning of a wood material exist

state 4

the total amount of thermal energy that could be generated by the combustion reaction if a fuel were completely burned is known as

heat of combustion

the energy released per unit of time as a given fuel burns is known as the

heat release rate

what is the primary oxidizing agent in most fires

oxygen in the atmosphere

at room temperature what is the minimum concentration of atmospheric oxygen that will support combustion

14%

oxygen rich atmospheres are atmospheres

with concentrations of oxygen that exceed 23.5%

which would not be considered a common oxidizer

noble gases

according to OSHA any atmosphere having less than ___oxygen in the air as being oxygen deficient an a hazer to firefighter snot wearing SCBA

19.5%

in which of the following occupancies may you expect to find oxygen enriched atmospheres

hospitals, industrial occupancies, and private homes

what would be the flammable range of propane

2.1-9.5%

what would be the flammable range of methane

5-15%

what would be the flammable range of ethanol

3.3-19%

some extinguishing agents such as halon interrupts the flame-producing chemical reaction and terminates the combustion reaction. this can be described as

extinquishment by chemical flame inhibition

which of the following potential fuel packages would you estimate to have the lowest hrr

small wastebasket

smoke generated from fire contains toxic or asphyxiate gases. which of the following would not be considered one such gas

water vapor H2O

the most common hazardous material contained in smoke is

carbon monoxide CO

which compound acts as a chemical asphyxiate by binding with hemoglobin in the blood

carbon monoxide

which compound acts as a chemical asphyxiate by preventing the body from using oxygen at the cellular level

hydrogen cyanide

which compound is a product of complete combustion of organic materials

carbon dioxide

class a fires are fires involving ordinary combustible materials such as all of the following except

gasoline

water is commonly used to extinguish class a fires by cooling the material below its ignition temperature. class a foams are used to enhance waters ability to extinguish class a fires by

reducing the water surface tension allowing it to penetrate more easily into the burning material

all of the following materials would be classified as a class b fire except

burning rubber

which is the most effective method of extinguishing a class b fire

inhibiting the chain reaction

energized electrical equipment and household appliances would be classified as

class c fires

the safest way to fire a class c fire is to

de-energize the source and then treat the fire as a class a or class b

class d fires are those that involve combustible metals. which of the following would not be considered a combustible metal

carbon

which extinguishing agent should never be used to extinguish a class c fire

water

class b fuels would include all of the following except

garbage

anything that occupies space and has mass is known as

matter

____is the capacity to perform work, occurs when a force is applied to an object over a distance, or when a chemical, biological, or physical transformation is made in a substance

energy

materials produced and released during burning best describes which of the following

products of combustion

a __is defined as a fire that occurs within an enclosed room or space within a building

compartment fire

in compartment fires, when the fuel available to burn is limited , the fire is said to be ___likewise if the amount of available oxygen is limited the condition is known as

fuel controlled, ventilation controlled

linseed oil rags igniting would be an example of which of the following

auto ignition

piloted ignition is caused by

a spark or flame

the first stage of the burning process in a confined space in which the substance being oxidized producing heat is called the

incipient

when a fire is ignited by a spark or a flame it is refereed to as

piloted ignition

during the incipient stage of a fire hot gases begin to spread horizontally across the ceiling of a compartment. this is called

mushrooming and or ceiling jet

at which stage of a fire is fuel and oxygen virtually unlimited, and is characterized by the rapid release of heat

growth

___occurs where flames move through or across the unburden gases at the top of a compartment during a fires progression

rollover

rollover differs from flash over in that

only the flammable gases are burning and not the room contents

one of the most important physical properties that a firefighter should know about smoke is that smoke is

unburden fuel that is ready to ignite

at which of the following temperatures can a flash over occur

900-1200 degrees

initiation of combustion of a material by an internal chemical or biological reaction that has produced sufficient heat to ignite the material known as

spontaneous ignition

which are typical characteristics of a potential back draft

black smoke becoming dense gray yellow with little or no visible flame, smoke leaving the structure in puffs or intervals, pressurized smoke exiting through small openings

a method to help prevent back draft from occurring is to

open the structure at the highest point involved

which statement is not true

self oxidizing fuels can easily be extinguished by oxygen dilution

a broken natural gas line is on fire. your engine company turns off the shut off valve thus extinguishing the fire. this is an example of which of the following fire extinguishing methods

fuel removal

if a fire is in the smoldering phase of combustion, which of the following is not an option for extinguishing the fire

reduction of fuel

one of the most common methods of extinguishing fires is

temperature reduction by cooling with water

all of the following extingushing agents act by chemical flame inhibition except

carbon dioxide

the tendency or capacity to remain afloat in a liquid or rise in a gas is known as

buoyant

at what temperature does water turn to steam

212 degrees F

when wateris converted to steam it expands approximately ___times

1700

___is composed of at least one inlet opening, one exhaust opening, and the connecting volume between the opening

flow path

the buoyant layer of hot gases and smoke produced by afire in a compartment is called the

upper layer

a petroleum based organic compoud that contians only hydrogen and carbon is known as a

hydrocarbon fuel

a liquid having a flash point at or above 100 degrees F and below 200 degrees F is known as an

combustible liquid

a at normal oxygen levels, nomex does not burn, however when placed in an oxygen enriched atmosphere or approximately __oxygen it will burn vigorously

31%

molecular fragments that are highly reactive are called

free radicals

all buildings exchange air inside the structure with the air on the outside of the structure in which of the following ways

constructed openings such as windows, doors, and passive ventilation devices, leakages through cracks and other gaps in construction, heating ventilating and air contraindication systems

which statment regarding the role of ambient conditions on fire development are true

high humidity can impede the natural movement of smoke, cold temperatures can impede the natural movement of smoke, wind speed and direction can be extremely significant in fire development

the level at a compartement opening where the difference in pressue exerted by expansion and buoyancy of hot smoke floating out of the opening in the inward pressure of cooler ambient temperature air flowing in through an opening is equal is known as

neutral plane

over the years, the fire service has coin words, and phrases to describe various fire events that result in rapid fire development these would include all of the following but

mushrooming