NFPA 921 COMPREHENSIVE EXAM UPDATED
QUESTIONS AND ANSWERS SURE A+
✔✔Heat and Flame Vector. - ✔✔An arrow used in a fire scene drawing to show the
direction of heat, smoke, or flame flow.
✔✔Heat Flux - ✔✔The measure of the rate of heat transfer to a surface or an area,
typically expressed in kW/m2, or W/cm2.
✔✔Heat Release Rate - ✔✔The rate at which heat energy is generated by burning
✔✔Heat Transfer - ✔✔The exchange of thermal energy between materials through
conduction, convection, and/or radiation.
✔✔High Explosive - ✔✔A material that is capable of sustaining a reaction front that
moves through the unreacted material at a speed equal to or greater than that of sound
in that medium [typically 1000 m/sec (3000 ft/sec)]; a material capable of sustaining a
detonation. (See also 3.3.46, Detonation.)
✔✔High Order Damage - ✔✔A rapid pressure rise or high- force explosion
characterized by a shattering effect on the confining structure or container and long
missile distances.
,✔✔Hybrid Mixture - ✔✔An explosible heterogeneous mixture, comprising gas with
suspended solid or liquid particulates, in which the total flammable gas concentration is
≥10 percent of the lower flammable limit (LFL) and the total suspended particulate
concentration is ≥10 percent of the minimum explosible concentration.
✔✔Hypergolic Material - ✔✔Any substance that will spontaneously ignite or explode
upon exposure to an oxidizer.
✔✔Ignitible Liquid - ✔✔Any liquid or the liquid phase of any material that is capable of
fueling a fire, including a flammable liquid, combustible liquid, or any other material that
can be liquefied and burned.
✔✔Ignition - ✔✔. The process of initiating self-sustained combustion.
✔✔Ignition Energy - ✔✔The quantity of heat energy that should be absorbed by a
substance to ignite and burn.
✔✔Ignition Temperature - ✔✔Minimum temperature a substance should attain in order
to ignite under specific test conditions..
✔✔Layering - ✔✔The systematic process of removing debris from the top down and
observing the relative location of artifacts at the fire scene.
✔✔Low Explosive - ✔✔An explosive that has a reaction velocity of less than 1000
m/sec (3000 ft/sec).
✔✔Low Order Damage - ✔✔A slow rate of pressure rise or low-force explosion
characterized by a pushing or dislodging effect on the confining structure or container
and by short missile distances.
✔✔Ignition Time - ✔✔The time between the application of an ignition source to a
material and the onset of self-sustained combustion.
✔✔Material First Ignited - ✔✔The fuel that is first set on fire by the heat of ignition; to be
meaningful, both a type of material and a form of material should be identified.
✔✔Incendiary Fire. - ✔✔A fire that is intentionally ignited in an area or under
circumstances where and when there should not be a fire.
✔✔Inductive Reasoning - ✔✔The process by which a person starts from a particular
experience and proceeds to generalizations. The process by which hypotheses are
developed based upon observable or known facts and the training, experience,
knowledge, and expertise of the observer.
, ✔✔Isochar - ✔✔A line on a diagram connecting points of equal char depth.
✔✔Joule - ✔✔The preferred SI unit of heat, energy, or work. A joule is the heat
produced when one ampere is passed through a resistance of one ohm for one second,
or it is the work required to move a distance of one meter against a force of one newton.
There are 4.184 joules in a calorie, and 1055 joules in a British thermal unit (Btu). A watt
is a joule/second.
✔✔Kilowatt - ✔✔A measurement of energy release rate. (Heat)
2. A unit of power. A watt is a joule/second. One kilowatt = 1000 watts
✔✔Minimum Explosible Concentration (MEC). - ✔✔The minimum concentration of a
combustible dust cloud that is capable of propagating a deflagration through a uniform
mixture of the dust and air under the specified conditions of test.
✔✔Noncombustible Material - ✔✔A material that, in the form in which it is used and
under the condition anticipated, will not ignite, burn, support combustion, or release
flammable vapors when subjected to fire or heat.
✔✔Non flammable - ✔✔Not readily capable of burning with a flame. (2) Not liable to
ignite and burn when exposed to flame. Its antonym is flammable.
✔✔Ohm - ✔✔The SI unit of electrical impedance or, in the direct current case, electrical
resistance.
✔✔Overcurrent - ✔✔Any current in excess of the rated current of equipment or the
ampacity of a conductor; it may result from an overload, short circuit, or ground fault.
✔✔Overhaul - ✔✔A fire fighting term involving the process of final extinguishment after
the main body of the fire has been knocked down. All traces of fire must be extinguished
at this time.
✔✔Overload - ✔✔Operation of equipment in excess of normal, full-load rating or of a
conductor in excess of rated ampacity that, where it persists for a sufficient length of
time would cause damage or dangerous overheating. A fault, such as a short circuit or
ground fault, is not an overload.
✔✔Passive Fire Protection System - ✔✔Any portion of a building or structure that
provides protection from fire or smoke without any type of system activation or
movement.
✔✔Plume - ✔✔The column of hot gases, flames and smoke rising above a fire; also
called convection column, thermal updraft, or thermal column.
QUESTIONS AND ANSWERS SURE A+
✔✔Heat and Flame Vector. - ✔✔An arrow used in a fire scene drawing to show the
direction of heat, smoke, or flame flow.
✔✔Heat Flux - ✔✔The measure of the rate of heat transfer to a surface or an area,
typically expressed in kW/m2, or W/cm2.
✔✔Heat Release Rate - ✔✔The rate at which heat energy is generated by burning
✔✔Heat Transfer - ✔✔The exchange of thermal energy between materials through
conduction, convection, and/or radiation.
✔✔High Explosive - ✔✔A material that is capable of sustaining a reaction front that
moves through the unreacted material at a speed equal to or greater than that of sound
in that medium [typically 1000 m/sec (3000 ft/sec)]; a material capable of sustaining a
detonation. (See also 3.3.46, Detonation.)
✔✔High Order Damage - ✔✔A rapid pressure rise or high- force explosion
characterized by a shattering effect on the confining structure or container and long
missile distances.
,✔✔Hybrid Mixture - ✔✔An explosible heterogeneous mixture, comprising gas with
suspended solid or liquid particulates, in which the total flammable gas concentration is
≥10 percent of the lower flammable limit (LFL) and the total suspended particulate
concentration is ≥10 percent of the minimum explosible concentration.
✔✔Hypergolic Material - ✔✔Any substance that will spontaneously ignite or explode
upon exposure to an oxidizer.
✔✔Ignitible Liquid - ✔✔Any liquid or the liquid phase of any material that is capable of
fueling a fire, including a flammable liquid, combustible liquid, or any other material that
can be liquefied and burned.
✔✔Ignition - ✔✔. The process of initiating self-sustained combustion.
✔✔Ignition Energy - ✔✔The quantity of heat energy that should be absorbed by a
substance to ignite and burn.
✔✔Ignition Temperature - ✔✔Minimum temperature a substance should attain in order
to ignite under specific test conditions..
✔✔Layering - ✔✔The systematic process of removing debris from the top down and
observing the relative location of artifacts at the fire scene.
✔✔Low Explosive - ✔✔An explosive that has a reaction velocity of less than 1000
m/sec (3000 ft/sec).
✔✔Low Order Damage - ✔✔A slow rate of pressure rise or low-force explosion
characterized by a pushing or dislodging effect on the confining structure or container
and by short missile distances.
✔✔Ignition Time - ✔✔The time between the application of an ignition source to a
material and the onset of self-sustained combustion.
✔✔Material First Ignited - ✔✔The fuel that is first set on fire by the heat of ignition; to be
meaningful, both a type of material and a form of material should be identified.
✔✔Incendiary Fire. - ✔✔A fire that is intentionally ignited in an area or under
circumstances where and when there should not be a fire.
✔✔Inductive Reasoning - ✔✔The process by which a person starts from a particular
experience and proceeds to generalizations. The process by which hypotheses are
developed based upon observable or known facts and the training, experience,
knowledge, and expertise of the observer.
, ✔✔Isochar - ✔✔A line on a diagram connecting points of equal char depth.
✔✔Joule - ✔✔The preferred SI unit of heat, energy, or work. A joule is the heat
produced when one ampere is passed through a resistance of one ohm for one second,
or it is the work required to move a distance of one meter against a force of one newton.
There are 4.184 joules in a calorie, and 1055 joules in a British thermal unit (Btu). A watt
is a joule/second.
✔✔Kilowatt - ✔✔A measurement of energy release rate. (Heat)
2. A unit of power. A watt is a joule/second. One kilowatt = 1000 watts
✔✔Minimum Explosible Concentration (MEC). - ✔✔The minimum concentration of a
combustible dust cloud that is capable of propagating a deflagration through a uniform
mixture of the dust and air under the specified conditions of test.
✔✔Noncombustible Material - ✔✔A material that, in the form in which it is used and
under the condition anticipated, will not ignite, burn, support combustion, or release
flammable vapors when subjected to fire or heat.
✔✔Non flammable - ✔✔Not readily capable of burning with a flame. (2) Not liable to
ignite and burn when exposed to flame. Its antonym is flammable.
✔✔Ohm - ✔✔The SI unit of electrical impedance or, in the direct current case, electrical
resistance.
✔✔Overcurrent - ✔✔Any current in excess of the rated current of equipment or the
ampacity of a conductor; it may result from an overload, short circuit, or ground fault.
✔✔Overhaul - ✔✔A fire fighting term involving the process of final extinguishment after
the main body of the fire has been knocked down. All traces of fire must be extinguished
at this time.
✔✔Overload - ✔✔Operation of equipment in excess of normal, full-load rating or of a
conductor in excess of rated ampacity that, where it persists for a sufficient length of
time would cause damage or dangerous overheating. A fault, such as a short circuit or
ground fault, is not an overload.
✔✔Passive Fire Protection System - ✔✔Any portion of a building or structure that
provides protection from fire or smoke without any type of system activation or
movement.
✔✔Plume - ✔✔The column of hot gases, flames and smoke rising above a fire; also
called convection column, thermal updraft, or thermal column.
