physical science of fire can help firefighters
it translates into practical knowledge of fire behavior
remaining chemically the same, but changing in size, shape or appearance
Physical change
When a substance changes from one type of matter to another, it has had a
chemical reaction
the amount of energy that an object can release in the future
Potential
The energy possessed by a moving object is called
kinetic energy
The potential chemical energy of fuel in fire behavior is converted to
thermal energy
What type of reaction absorbs energy as it occurs
Endothermic
What type of reaction releases energy in the form of heat and sometimes light
Exothermic
The process of ignition causes pyrolysis in solid fuels and what in liquid fuels
vaporization
What is the most common form of ignition
Piloted
What mode of combustion produces a smoldering glow in a material's surface
Nonflaming
In what mode of combustion is a visible flame produced
Flaming
What are the elements necessary to create fire in the model represented by the fire triangle
Fuel, oxygen, heat
Which of the following BEST describes what the fire tetrahedron represents
An uninhibited chemical chain reaction
What type of combustion occurs when burning is localized on or near a fuel's surface
Nonflaming
What product of combustion may heat adjacent fuels, making them susceptible to ignition
Thermal energy
What product of combustion causes the most fire deaths
Toxic smoke
What product of combustion is the most common product in structure fires
Carbon monoxide
describes why firefighters must use SCBA during overhaul
Volume and density of smoke may be reduced, but the hazard is not eliminated
describes kinetic energy transfer
It moves from high-temperature to low-temperature substances.
What source of thermal energy is the most common source of heat in combustion reactions
Chemical energy
Which of the following sources of energy is a form of oxidation
Self-heating
What method of electrical energy occurs when a high-temperature luminous discharge crosses a gap
Arcing
What method of heat transfer occurs when a material is heated as the result of direct contact with a heat source
Conduction
What heat transfer method usually occurs through movement of hot smoke and fire gases
Convection
What method of heat transfer can become the dominant mode as the fire grows in size
Radiation
the influence of exposed surfaces on radiant heat
Dark materials emit and absorb heat more effectively than light materials
Which type of fuel does not contain carbon
Inorganic
the total amount of energy released when a specific amount of fuel is burned
Heat of combustion
Heat release rate is usually expressed in which of the following measurements
Kilowatts (kW)
What type of fuel can be the most dangerous of all the types
Gaseous
What type of fuel has mass and volume but no definite shape
Liquid
Liquids with a specific gravity of less than 1 will
float on the surface.
describes what vapor pressure indicates
How easily a substance will evaporate
the minimum temperature at which a liquid gives off sufficient vapors to ignite, but still not sustain combustion
Flash point
What term is used to describe the extent to which a substance will mix with water
Solubility
What type of fuel has a definite size and shape
Solid
is used to refer to the process that can generate sufficient quantities of burnable vapors to ignite in the presence of a sufficient oxidizer
Pyrolysis
Fuel particles become smaller as the ratio of surface-to-mass
increases
The primary oxidizing agent in most fires is
oxygen
describes the impact of higher oxygen concentration on combustion
Materials burn more intensely
the minimum concentration of fuel vapor and air that supports combustion
Lower flammable limit
the complete oxidation of methane will produce
carbon dioxide and water
the impact of an extinguishing agent when trying to extinguish flaming combustion
it forms a stable product
development factors that affects heat release rate
Fuel type
What fire development factor is based on considering how the volume of air will impact radiated heat in a fire
Compartment volume and ceiling height
What form of compartment fire is controlled by the availability of oxygen and the configuration of fuel
Fuel-controlled
What thermal property of a compartment contains heat within the compartment, causing localized increase in temperature
Insulation
What fire development factor includes cold temperature, strong winds, and wind direction
Ambient conditions
In what stage is fire development largely dependent on the characteristics and configuration of the fuel involved
Incipient
Which of the following affects the amount of air entrained in the plume during the growth stage
Location of fuel package
What is defined as the tendency of gases to form into layers according to temperature
Thermal layering
The neutral plane in the growth stage is the
interface of hot and cool layers at an opening
Isolated flames in the gas layer during the growth stage indicates
that portions of the layer are within flammable range
What stage of fire development occurs when all the combustible materials in a compartment are burning
Fully Developed
What fire stage occurs as the fuel is consumed and oxygen concentration falls
Decay
What type of rapid fire development happens when all the combustible materials and gases in a compartment ignite almost simultaneously
Flashover
What common element of flashover represents the shift from growth stage to fully developed stage
Transition in fire development
Which of the following is a heat indicator of a possible flashover
Darkened windows
The ignition of unburned fire gases at the top of the compartment is known as
rollover
What aspect of fire development is a result of an increase in low-level ventilation prior to upper level ventilation
Backdraft
Which of the following is a building indicator for a possible backdraft
Fire confined to a void space
Which of the following is a heat indicator for a possible backdraft
Smoke stained windows
What type of rapid fire development occurs as unburned fuel gases contact an ignition source
Smoke explosion
What is the most common method used in fire fighting operations
Temperature reduction
Water is converted to steam at
212F (100C).
What method of fire suppression is the simplest
Fuel removal
What fire-suppression method does not work if fuel is self-oxidixing
Oxygen exclusion
What suppression method uses extinguishing agents to stop flame production
Chemical flame inhibition
What fire behavior can be the result of wind from outside the structure
Unplanned ventilation
Which of the following terms is the minimum temperature at which a liquid gives off sufficient vapors to ignite, but still not sustain combustion?
Flash Point
The amount of heat necessary to raise one gram of water 1 degree Celsius is known as a
joule
The lowest temperature at which a combustible material ignites in the air without a spark or flame is known as the
Auto ignition Temp.
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
What suppression method involves the introduction of air or removal of hot gases and smoke from a building?
Ventilation
Heat of combustion is usually expressed in which of the following measurements?
Kilojoules/gram
Which is the most common source of heat in combustion reactions?
Chemical energy
Iron rusting is a prime example of which of the following reactions?
Oxidation Reaction
In what aspect of fire development will the environment of a room change from a two-layer condition to a single well mixed, untenable hot gas condition?
flashover
The chemical decomposition of a substance through the action of heat is called
Pyrolysis
An oxidizer would be defined as
A material that yields oxygen or other oxidizing gases during the course of a chemical reaction.
Materials that absorb heat but do not participate actively in a combustion reaction are known as
Passive agents
The fuel that is being oxidized or burned during combustion is referred to as a
reducing agent
Chemical reactions in which a substance absorbs heat energy are called
Endothermic heat reactions
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
In the SI system the unit for "work" is
Joule
When a current flowing through a conductor exceeds its design limits, it may overheat and present an ignition hazard. This type of heating is called
Over current and overload
The four main components of the Fire Tetrahedron include fuel, heat, oxygen and
self-sustained chemical reaction
generated when gas is compressed.
Heat of compression
What is a form of energy characterized by vibration of molecules and capable of initiating in supporting chemical changes and changes of state.
Heat
Forms of ignition
Auto and piloted
which of the following fire development factors affects heat release rate?
fuel type
The study of the physical world around us that includes the sciences of chemistry and physics is called
physical Science
The amount of energy delivered over a period of time is called
Power
The 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 is known as
Vapor Density
What common element of flashover is not an instantaneous spread of complete involvement but happens within seconds?
Rapidity
What fire development factor is based on considering how the volume of air will impact radiated heat in a fire?
Compartment volume and ceiling height
What best describes the relationship needed for the release of potential chemical energy in fuel?
Thermal kinetic energy is needed to release it
Liquids with a specific gravity greater than 1 will:
sink below the surface
Energy exists in which of the following states?
kinetic and potential