NFPA 921 EXAM SCRIPT 2025/2026 QUESTIONS WITH
ANSWERS GRADED A+
✔✔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. - ✔✔3.3.26 Cause.
✔✔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 - ✔✔3.3.27 Ceiling Jet.
✔✔A buoyant layer of hot gases and smoke
produced by a fire in a compartment. - ✔✔3.3.28 Ceiling Layer.
✔✔Carbonaceous material that has been burned or
pyrolyzed and has a blackened appearance. - ✔✔3.3.29 Char.
✔✔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. - ✔✔3.3.30 Char Blisters.
✔✔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. - ✔✔3.3.31 Clean Burn.
✔✔Capable of undergoing combustion. - ✔✔3.3.32* Combustible.
✔✔An instrument that samples air and indicates whether there are ignitible vapors or
gases present. - ✔✔3.3.33* Combustible Gas Indicator.
✔✔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. - ✔✔3.3.35 Combustion.
✔✔The heat, gases, volatilized liquids and solids, particulate matter, and ash generated
by combustion. - ✔✔3.3.36 Combustion Products.
✔✔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. - ✔✔3.3.37
Competent Ignition Source.
, ✔✔Heat transfer to another body or within a
body by direct contact. - ✔✔3.3.38 Conduction.
✔✔Heat transfer by circulation within a medium such as a gas or a liquid. - ✔✔3.3.39
Convection.
✔✔The tendency of a material to move or deform
permanently to relieve stresses. - ✔✔3.3.40 Creep.
✔✔A flow of electric charge. - ✔✔3.3.41 Current.
✔✔The process by which conclusions are drawn by logical inference from given
premises. - ✔✔3.3.42 Deductive Reasoning.
✔✔Propagation of a combustion zone at a
velocity that is less than the speed of sound in the unreacted
medium. [68, 2013] - ✔✔3.3.43 Deflagration.
✔✔The mass of a substance per unit volume,
usually specified at standard temperature and pressure. The density of water is
approximately one gram per cubic centimeter. The density of air is approximately 1.275
grams per cubic meter. - ✔✔3.3.44 Density.
✔✔(1) Sensing the existence of a fire, especially
by a detector from one or more products of the fire, such as smoke, heat, infrared
radiation, and the like. (2) The act or process of discovering and locating a fire. -
✔✔3.3.45 Detection.
✔✔Propagation of a combustion zone at a
velocity greater than the speed of sound in the unreacted medium. [68, 2013 -
✔✔3.3.46 Detonation.
✔✔A gas, vapor, dust, particulate, aerosol,
mist, fog, or hybrid mixture of these, suspended in the atmosphere, which is capable of
being ignited and propagating a flame front. - ✔✔3.3.47 Diffuse Fuel.
✔✔A flame in which fuel and air mix or diffuse together at the region of combustion. -
✔✔3.3.48 Diffusion Flame.
✔✔The spread of fire by the dropping or falling
of burning materials. Synonymous with "fall down." - ✔✔3.3.49 Drop Down.
ANSWERS GRADED A+
✔✔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. - ✔✔3.3.26 Cause.
✔✔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 - ✔✔3.3.27 Ceiling Jet.
✔✔A buoyant layer of hot gases and smoke
produced by a fire in a compartment. - ✔✔3.3.28 Ceiling Layer.
✔✔Carbonaceous material that has been burned or
pyrolyzed and has a blackened appearance. - ✔✔3.3.29 Char.
✔✔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. - ✔✔3.3.30 Char Blisters.
✔✔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. - ✔✔3.3.31 Clean Burn.
✔✔Capable of undergoing combustion. - ✔✔3.3.32* Combustible.
✔✔An instrument that samples air and indicates whether there are ignitible vapors or
gases present. - ✔✔3.3.33* Combustible Gas Indicator.
✔✔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. - ✔✔3.3.35 Combustion.
✔✔The heat, gases, volatilized liquids and solids, particulate matter, and ash generated
by combustion. - ✔✔3.3.36 Combustion Products.
✔✔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. - ✔✔3.3.37
Competent Ignition Source.
, ✔✔Heat transfer to another body or within a
body by direct contact. - ✔✔3.3.38 Conduction.
✔✔Heat transfer by circulation within a medium such as a gas or a liquid. - ✔✔3.3.39
Convection.
✔✔The tendency of a material to move or deform
permanently to relieve stresses. - ✔✔3.3.40 Creep.
✔✔A flow of electric charge. - ✔✔3.3.41 Current.
✔✔The process by which conclusions are drawn by logical inference from given
premises. - ✔✔3.3.42 Deductive Reasoning.
✔✔Propagation of a combustion zone at a
velocity that is less than the speed of sound in the unreacted
medium. [68, 2013] - ✔✔3.3.43 Deflagration.
✔✔The mass of a substance per unit volume,
usually specified at standard temperature and pressure. The density of water is
approximately one gram per cubic centimeter. The density of air is approximately 1.275
grams per cubic meter. - ✔✔3.3.44 Density.
✔✔(1) Sensing the existence of a fire, especially
by a detector from one or more products of the fire, such as smoke, heat, infrared
radiation, and the like. (2) The act or process of discovering and locating a fire. -
✔✔3.3.45 Detection.
✔✔Propagation of a combustion zone at a
velocity greater than the speed of sound in the unreacted medium. [68, 2013 -
✔✔3.3.46 Detonation.
✔✔A gas, vapor, dust, particulate, aerosol,
mist, fog, or hybrid mixture of these, suspended in the atmosphere, which is capable of
being ignited and propagating a flame front. - ✔✔3.3.47 Diffuse Fuel.
✔✔A flame in which fuel and air mix or diffuse together at the region of combustion. -
✔✔3.3.48 Diffusion Flame.
✔✔The spread of fire by the dropping or falling
of burning materials. Synonymous with "fall down." - ✔✔3.3.49 Drop Down.
