Chapter 2 Fire Behavior Flashcards
in _______ Combustion, oxidation involves fuel in the gas phase
Flaming
Some solid fuels, particularly those that are porous in can char, undergo oxidation at the surface of the fuel. This is known as ____ or _____combustion
Non flaming, Smoldering
________ Energy is kinetic energy associated with the movement of the Atoms and molecules that comprise matter
Thermal
_______ Is a measurement of kinetic energy
Temperature
_______ Is the capacity to perform work
Energy
It takes _______Joules to raise the temperature of 1 kg of water 1°C
4186
One ____Is the amount of heat required to raise the temperature of 1 pound of water 1°F
BTU
Amount of heat energy required to raise the temperature of 1 pound of water 1°F
British thermal unit
____Ignition occurs when a mixture of fuel and oxygen encounters an ignition source with sufficient heat energy to start the combustion reaction
Piloted
________ Occurs without any external flame or spark to ignite the fuel gases or vapors
Auto ignition
Total amount of thermal energy that can be generated by the combustion reaction if a fuel were completely burned
Heat of combustion
The _______ Of a given fuel is the total amount of energy released on a specific amount of the fuel is oxidized
Heat of combustion
________ Is the energy released per unit of time as a given fuel burns
Heat release rate
_________ Is the transfer of heat energy by direct contact
Conduction
________ Is the transfer of heat energy as an electromagnetic wave without and intervening medium
Radiation
__________ Is the transfer of heat energy by a fluid or gas
Convection
________ is the dominant method of heat transfer in the early stages of fire development
Convection
Transfer of heat by the movement of heated fluid or gas is usually in an upward direction
Convection
_________ Is the tendency of gases to stratify according to temperature
Thermal layering
When fire development is limited by a lack of oxygen, the fire I said to be__________
Ventilation controlled
When the fire is fuel control, increased_____will greatly reduce temperatures within the compartment and thereby slow or prevent it’s progression to flash over
Ventilation
The ceiling temperature approaches_____degreesF during a rollover and the heat being radiated to the floor may be sufficient to ignite ordinary materials such as newspaper
1,100
Scientific measurement of how much heat is available for transfer to human skin
Heat flux
As temperature and____continue to increase, the compartment may rapidly transition to full involvement with or without flash over
Heat flux
In the incipient and early girl stages of mini compartment fires, heat transfer is largely dependent on_____
Convection
A Fire may enter the_____stage due to consumption of available fuel or due to limited oxygen supply
Decay
Two potential consequences of the introduction of air to the compartment in the____stage are ventilation induced flashover and Backdraft
Decay
If a fire is_____, it can be thought of as being similar to a gasoline engine running with the choke closed
Ventilation controlled
In a ____fire, increasing the air supply increases the heat release rate
Ventilation controlled
If the concentration of flammable combustion and pyrolysis products is above the upper flammable limit, the temperature is above___degreesF or another source of ignition is available, and ventilation is increased, a back draft may occur
1,100
It is important to recognize that most compartment fires that grow beyond the incipient stage become________
Ventilation controlled
In a compartment fire, the most fundamental fuel characteristics influencing fire development are_______and_______
Mass, surface area
_________ is the layout of the structure including the number of stories, avenues for fire spread, compartmentation, and barriers to fire spread
Building configuration
_________ is the actual and potential ventilation of a structure based on structural openings, construction type, and building ventilation systems
Existing Ventilation
_________ Properties include installation, heat reflectivity, retention, and conductivity
Thermal
The _________ Of fuel influences it’s heat of combustion and the heat release rate
Chemical composition
Kilojoules per kilogram is a standard unit of measure for_______
Heat of combustion
_________ are indicators of potential fire behavior prior to ignition
Building features
The first of the critical building features is_______
Construction type
The__________ In a structure is the actual and potential airflow based on natural air currents, structural openings, construction types, and building ventilation systems
Existing Ventilation
_______ Is a result of incomplete combustion
Smoke
Smoke color, density, pressure, and movement or other indicators of_________
Fire behavior
Fires that are ventilation controlled tend to produce a greater volume of________ than those that are fuel controlled
Smoke
This color of smoke generally results from an under ventilated fire or combustion of petroleum products
Dark smoke
This color of smoke is produced from petroleum products, rubber, and many plastics
Black smoke
This color of smoke frequently contains a substantial concentration of toxic and flammable pyrolysis products
Light colored smoke
This color smoke is produced from wood and other ordinary combustibles But may produce black smoke on the fire has a limited air supply
Light grey to yellowish or dark brown
The term _______ refers to the buoyancy of the smoke
Physical density
Gradual lowering of the hot gas layer could indicate deteriorating conditions and increase potential for_______
Flashover
_________ Refers to the movement of air toward burning fuel in the movement of smoke out of the compartment
Airflow
_________ indicators include pressure and velocity, turbulence, direction, and movement of the hot gas layer
Air flow
For a given volume of smoke, velocity and turbulence will be greater through ________ openings
Smaller
_______ Airflow is indicative of an under ventilated fire with potential Backdraft conditions
Pulsing
Visual indicators of____include observed effects such as blistering paint, bubbling roof tar, crazing glass, and blackened windows
Heat
If firefighters can see flames in the hot gas layer it may indicate _______and impending rollover
Ghosting
A bright_______ flame usually indicates high temperatures such as that generated by burning magnesium and other combustible metals
White
There are two mechanisms that can induce flash over _____and ______
Radiation, ventilation
________ Is a heat driven phenomenon
Flash over
Nearing flashover,______heat becomes the dominant method of heat transfer, and the heat flux is sufficient to quickly raise the temperature of the fuel package in the compartment to their ignition temperature temperature
Radiant
An increase in ventilation can result in a___called a backdraft
Deflagration
Instantaneous explosion or rapid burning of superheated gases that occurs when oxygen is introduced into an oxygen depleted confined space
Backdraft
The effects of a Backdraft can vary considerably depending on the number of factors. These variables include the following
Where ignition occurs
Speed at which air and fuel mix
Degree of confinement
Volume of flammable products of combustion
A ________ Is a form of fire gas ignition that is, the ignition of accumulated final products of combustion
Smoke explosion
The key differences between a backdraft and a smoke explosion are the___at the fire gases and the oxygen concentration
Temperature
IFSTA essentials of fire fighting provide a solid foundation for developing knowledge of basic fire science and fire dynamics, referred to as ______
Fire behavior
And exothermic chemical reaction that is self-sustaining process of rapid oxidation of a fuel, that produces heat and light
Combustion
_______ Is the energy contained in an object that may be released in the future
Potential energy
_______ Is often defined in formally as energy of motion
Kinetic energy
IFSTA‘s essential of firefighting provides a solid foundation for developing knowledge of basic fire science and fire dynamics, and I referred to as _______
Fire behavior
_______ is termed is a rapid and self sustaining chemical process that yields heat and usually light
Combustion
The fire triangle is a simple model that explains nonflaming or surface combustion such as ________
Glowing charcoal
Heat is a form of energy, and energy exist in two states:_____&____
Potential, kinetic
______ Is the movement of thermal energy from objects of higher temperature to those of lower temperature
Heat
While a ____ is defined as being equal to one Newton over a distance of 1 m, in relation to fire behavior it is more relevant to think of joules in terms of heat
Joule
There are two forms of ignition_____&_______
Piloted ignition, autoignition
the _____ of any fuel determines its heat of combustion and has a significant influence on its energy or heat release rate
Chemical content
Heat of combustion is usually expressed in either_____ or______
Kilojoules/gram, megajoules/kilogram
Heat release rate is dependent on the ____, _______, and _____ of the fuel
Type, quantity, orientation
Convection is the dominant method of heat transfer in the early stages of fire development. However, as the room approaches full involvement, _____from flames and the hot gas layer become The more dominant method of heat transfer
Radiation
 The incipient stage starts with _____the point worth the three elements of the fire triangle come together and combustion begins
Ignition
Thermal layering is the tendency of gases to stratify according to temperature. Other terms sometimes used to describe this tendency are _____&_______
Heat stratification, thermal balance
When sufficient oxygen is available, fire development is controlled by the ____ and ____ of the fuel
Characteristics, configuration
A significant factor influencing the rate of development is how the fuel is ________
Oriented relative to horizontal
If flash over occurs and it does not in every case it will look her as the fire transitions from the _____ to the ______stage
Growth stage, fully developed
The _____ Of a given fuel is the total amount of energy released when a specific amount of that fuel is oxidized
Heat of combustion
In the incipient and early growth stages of mini compartment fires, heat transfer is largely dependent on_____
Convection
In the ______ stages of mini compartment fires, heat transfer is largely dependent on convection
Incipient and early growth
The availability of both ______ and _____ determine whether a fire within a compartment will progress to flash over
Fuel, oxygen
Two potential consequences of the introduction of air to the compartment in the decay stage are _____&______
Ventilation induced flashover, Backdraft
In a ventilation controlled fire, increasing the Air Supply increases the _____
HRR
Combustible materials with high ______ are much more easily ignited and will burn more quickly than the same substance with less surface area
Surface to mass ratios
In a compartment fire, the most fundamental fuel characteristics influencing fire development are_____&_______
Mass, surface area
The _____ Are often the most readily available fuel source in a compartment fire
Contents of a structure
When a fire develops to the point where it becomes ventilation controlled , the ____will determine the speed and extent of fire development and sometimes the direction of fire spread
Available air supply
Materials such as masonry act as a _____ and will retain heat energy, sustaining high temperatures for a long period of time
Heat sink
______ Windows, those with multiple layers separated by inert gases, can also act to contain heat in a developing fire
Thermal
Considering that most fires beyond the Incipient stage are or will quickly become ventilation controlled, changes in ______ are likely to be one of the most significant factors in changing fire behavior
Ventilation
The chemical composition of fuel influences its _____, the amount of heat released by a given mass of fuel, and the _______, the rate at which the heat is released
Heat of combustion, heat release rate
______ Of a specific amount of fuel release is a given amount of heat energy
Oxidation
A fuels heat of combustion is dependent on its _______ and the heat of combustion for hydrocarbon fuels such as plastics, gasoline, propane, and methane can be considerably higher than that of cellulos fuels such as wood
Chemical content
Fires that are ______ tend to produce a greater volume of smoke than those that are_______
Ventilation controlled, fuel controlled
Wood and other ordinary combustibles produce various shades of ___ smoke
Gray
The terms ____ and ____ are used to describe how difficult it is to see through the smoke
Optical density, opacity
______&_____smoke contains a high concentration of partifles and is difficult to see through
Optically dense, thick
Like color, optical density is related to _____&_______
Fuel type, ventilation
In general, buoyancy is related to the _____ of the smoke the higher the temperature, the greater the buoyancy
Temperature
Even more important than the height of the gas layer are changes in its height. A ______ could indicate that some type of ventilation has occurred either tactically by firefighters or caused by the fire breaking a window
Sudden rise
_______ of the hot gas layer could indicate deteriorating conditions and increased potential for flashover
Gradual lowering
_______ could indicate deteriorating conditions caused by flashover in an adjacent compartment
Sudden lowering
Earflow is caused by pressure differential‘s inside and outside the compartment and by _____,differences in density between a hot smoke and cooler hair
Gravity current
Airflu indicators include pressure and ____,____,_____&_______of the hot gas layer
Velocity, turbulence, direction, movement
Fire stream effects such as evaporation of water from hot surfaces or lack of return from a ______, brief application of water fog into the hot gas layer to check for heat overhead, also provide an indication of elevated temperature
Temperature check
_______ Perceptible by touch, include sensing temperature or temperature changes
Tactile effects
Flame color is largely dependent on the type of fuel involved, but if flames go from _______, it may also indicate reduced oxygen
Light yellow to reddish orange
Wildland firefighters refer to high rates of fire spread and heat output that preclude offensive suppression methods as_______
Extreme fire behavior
Extreme fire behavior is the result of ______ leading to flashover, which is followed by a sustained increase in heat output
Rapid fire development
Extreme fire behavior is the result of rapidfire development leading to flashover, which is followed by a sustained increase in heat output. On the other hand, rapid combustion or an explosion of accumulated fire gases is an example of a________and is more characteristic of Backdraft or other fire gas ignition‘s
Transient event
Flashover is a______
Heat driven phenomenon
______ Is defined by its characteristics progressing rapidly from intense burning to full involvement
Flashover
While _______ movement is commonly recognized as a Backdraft indicator, raising and lowering of the bottom of the hot gas layer is not
Pulsing smoke
To some degree, the violence of Backdraft is dependent on the extent to which the ______is confined
Fuel air mixture
Unlike ghosting or rollover, a smoke explosion involves ignition of a mixture of air and flammable combustion products that are already within the ______
Flammable range
The key differences between a Backdraft and a smoke explosion are the______&_________
Temperature of the fire gases, oxygen concentration
In the case of heat, _____means increasing temperature causing the average level of kinetic energy within the molecules of a substance to increase
Work
A ______ is a form of fire gas ignition that is, the ignition of accumulated flammable products of combustion
Smoke explosion
As smoke begins to accumulate in the compartment, it does so in a manner called ______
Thermal layering
The ___ and _____  Of smoke discharge from a burning building can provide some indication of fire location and extent but these indicators need to be verified
Volume, location
_____and _____ In the fire environment can affect the volume of smoke produced and how it behaves
Temperature, humidity
In structure fires, fire behavior is often a______
Sequential phenomenon
A ventilation controlled compartment fire in the decay stage can produce a large volume of flammable smoke and other gases due to_____
Incomplete combustion
_____and ______ can both result from increased air supply to a ventilation controlled fire
Ventilation induced flashover, Backdraft
