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NAFI CFEI EXAM 2025 ACTUAL EXAM PRACTICE QUESTIONS AND DETAILED CORRECT ANSWERS WITH RATIONALES
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NAFI CFEI EXAM 2025 ACTUAL EXAM PRACTICE QUESTIONS AND DETAILED CORRECT ANSWERS WITH RATIONALES
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NAFI CFEI EXAM 2025 ACTUAL EXAMPRACTICE QUESTIONS AND DETAILED
CORRECT ANSWERS WITH
RATIONALES
Deflagrations are propagating reactions, a subtype of
chemical explosions, and as such are
defined in which of the following definitions? (There may
be more than one correct choice.)
A. The energy is transferred from the reaction zone to the
unreacted zone on a reactive
shockwave.
B. The velocity of the reaction is always greater than the
speed of sound.
C. Structural damage is uniform and omnidirectional.
D. Relatively widespread evidence of burning, scorching,
and blistering result. Correct Answer C and D.
Deflagrations are propagating reactions in which the
energy transfer is accomplished through ordinary
process such as heat and mass transfer. The rate of
such reactions is controlled by the rate of the
particular transfer phenomena but at a velocity that is
less than the speed of sound (subsonic).
Deflagrations usually results in structural damage that
is uniform and
omnidirectional and thus a widespread evidence of
burning, scorching, and blistering.
,Identify the two major types of explosions from the choices
below.
A. Explosions that originate from strictly physical
phenomena, such as a boiler explosion
B. Explosions that originate due to the rapid combination
of ammonium nitrate and fuel oil(ANFO)
C. Explosions in which a chemical reaction is a source of
the high-pressure gas
D. Explosion that is the result of rapid expansion of gas
due to the Rickover Effect Correct Answer A and C
Mechanical, physical, and chemical are the three
major types of explosions.
However, there are several subtypes within each
classification
Dust explosions occur in a wide variety of materials.
Regardless of the material, which of the following factor(s)
is / are fundamental for an analysis of a dust explosion?
(There may be more than one Correct Answer.)
A. Particle size of the dust
B. Moisture of the dust particle
C. Turbulence within the suspended dust-air mixture
D. Concentration of the dust in air
E. Ignition temperature of the dust Correct Answer All of
them
It is helpful to characterize the explosion incident on the
basis of the damage that has occurred to the structure.
,The following recommended terms have been used to
classify the incidents.
A. High-grade damage
B. Medium-effect damage
C. High-order damage
D. Low-order damage Correct Answer C and D.
The terms high-order damage and low-order damage
have used to characterize
explosion damage. These terms are recommended to
reduce confusion with similar terms used
to describe the energy release from explosions.
A boiling liquid expanding vapor explosion will produce a
seated explosion if which two of
the following conditions occur?
A. The relief valve lifts at 125 percent of the designated
pressure.
B. The rate of pressure release from the vessel is
sufficiently rapid.
C. The confining vessel is of a small (sufficiently small)
size.
D. Fire fighters place a water stream on the vapor portion
of the vessel rather than on the liquid
portion of the vessel. Correct Answer B and C.
A boiling liquid expanding vapor explosion will
produce a seated explosion if the
confining vessel (such as a barrel or small tank) is of
a small size and if the rate of pressure
release at failure is rapid enough.
, Chemical explosions produce great quantities of heat.
Which of the following statements is true concerning
thermal effects?
A. Detonating explosions produce extremely high
temperatures of very limited duration.
B. Deflagration explosions produce lower temperatures
bet for much longer periods.
C. All of the above. Correct Answer C. All of the above.
The following parameters that are true for dust explosions
are also true for gas-vapor explosions. Identify the correct
relationships.
A. As in most gases and vapors, there is generally a
maximum limit of concentration. A maximum concentration
controls the reaction rate.
B. The rate of pressure rise and the maximum pressure
that occur in a dust explosion are higher if the pre-
explosion dust concentration is at or close to the optimum
mixture.
C. The combustion rate and maximum pressure decrease
if the mixture is fuel-rich or fuel-lean.
D. The rate of pressure rise and total explosion pressure
are very low at the lower explosive limit and at high fuel-
rich concentration. Correct Answer B, C, and D.
Which means of fire growth is considered "natural" when
examining a fire scene suspected of
multiple fires?
A. Fires on different stories
B. Fires spread through shafts
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