3.3.9 Arc Mapping correct answers The systematic evaluation of the electrical circuit configuration, spatial relationship of the circuit components, and identification of electrical arc sites to assist in the identification of the area of origin and analysis of the fire's spread.
3.3.12 Area of ...
NFPA 921 Highlights || with Complete Solutions.
3.3.9 Arc Mapping correct answers The systematic evaluation of the electrical circuit
configuration, spatial relationship of the circuit components, and identification of electrical arc
sites to assist in the identification of the area of origin and analysis of the fire's spread.
3.3.12 Area of Origin correct answers A structure, part of a structure, or general geographic
location within a fire scene, in which the "point of origin" of a fire or explosion is reasonably
believed to be located.
3.3.13 Arrow Pattern. correct answers A fire pattern displayed on the crosssection of a burned
wooden structural member.
3.3.16 Autoignition Temperature correct answers The lowest temperature at which a combustible
material ignites in air without a spark or flame.
3.3.17 Backdraft correct answers A deflagration resulting from the sudden introduction of air
into a confined space containing oxygendeficient products of incomplete combustion.
3.3.19 Blast Pressure Front correct answers The expanding leading edge of an explosion reaction
that separates a major difference in pressure between normal ambient pressure ahead of the front
and potentially damaging high pressure at and behind the front.
3.3.22 British Thermal Unit (Btu) correct answers The quantity of heat required to raise the
temperature of one pound of water 1°F at the pressure of 1 atmosphere and temperature of 60°F;
a British thermal unit is equal to 1055 joules, 1.055 kilojoules, and 252.15 calories.
3.3.25 Calorie correct answers The amount of heat necessary to raise 1 gram of water 1°C at the
pressure of 1 atmosphere and temperature of 15°C; a calorie is 4.184 joules, and there are 252.15
calories in a British thermal unit (Btu).
3.3.26 Cause. correct answers The circumstances, conditions, or agencies that brought about or
resulted in the fire or explosion incident, damage to property resulting from the fire or explosion
incident, or bodily injury or loss of life resulting from the fire or explosion incident.
3.3.27 Ceiling Jet correct answers A relatively thin layer of flowing hot gases that develops
under a horizontal surface (e.g., ceiling) as a result of plume impingement and the flowing gas
being forced to move horizontally.
3.3.30 Char Blisters. correct answers Convex segments of carbonized material separated by
cracks or crevasses that form on the surface of char, forming on materials such as wood as the
result of pyrolysis or burning.
3.3.31 Clean Burn correct answers A distinct and visible fire effect generally apparent on
noncombustible surfaces after combustible layer(s) (such as soot, paint, and paper) have been
, burned away. The effect may also appear where soot has failed to be deposited because of high
surface temperatures.
3.3.35 Combustion correct answers A chemical process of oxidation that occurs at a rate fast
enough to produce heat and usually light in the form of either a glow or flame.
3.3.37 Competent Ignition Source correct answers An ignition source that has sufficient energy
and is capable of transferring that energy to the fuel long enough to raise the fuel to its ignition
temperature.
3.3.43 Deflagration correct answers Propagation of a combustion zone at a velocity that is less
than the speed of sound in the unreacted medium.
3.3.46 Detonation correct answers Propagation of a combustion zone at a velocity greater than
the speed of sound in the unreacted medium.
3.3.52 Empirical Data correct answers Factual data that is based on actual measurement,
observation or direct sensory experience rather than on theory.
3.3.66 Fire correct answers A rapid oxidation process, which is a chemical reaction resulting in
the evolution of light and heat in varying intensities.
3.3.68 Fire Area correct answers The boundary of fire effects within a scene in which the area of
origin will be located. The fire area is characterized by identifying the border between damaged
and undamaged areas, which are distinguishable by fire effects and patterns created by flame,
heat, and smoke.
3.3.69 Fire Cause correct answers The circumstances, conditions, or agencies that bring together
a fuel, ignition source, and oxidizer (such as air or oxygen) resulting in a fire or a combustion
explosion.
3.3.84 Flammable Limits correct answers The upper or lower concentration limit at a specified
temperature and pressure of a flammable gas or a vapor of an ignitible liquid and air, expressed
as a percentage of fuel by volume that can be ignited.
3.3.87 Flash Fire correct answers A fire that spreads by means of a flame front rapidly through a
diffuse fuel, such as dust, gas, or the vapors of an ignitible liquid, without the production of
damaging pressure.
3.3.89 Flashover correct answers A transition phase in the development of a compartment fire in
which surfaces exposed to thermal radiation reach ignition temperature more or less
simultaneously and fire spreads rapidly throughout the space, resulting in full room involvement
or total involvement of the compartment or enclosed space.
3.3.102 Heat and Flame Vector correct answers An arrow used in a fire scene drawing to show
the direction of heat, smoke, or flame flow.
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