NAFI CFEI EXAM EVALUATION |CERTIFIED FIRE AND EXPLOSION
INVESTIGATOR (CFEI) NATIONAL ASSOCIATION OF FIRE
INVESTIGATORS (NAFI) - 2026/2027 NEWEST UPDATE COMPLETE
QUESTIONS AND CORRECT DETAILED ANSWERS WITH RATIONALES|
BRAND NEW VERSION!
EXAM OVERVIEW
The CFEI exam consists of 100 randomly selected questions from a pool maintained by the
National Certification Board. The primary reference source for exam questions is NFPA 921,
with additional references to NFPA 1033 and the NAFI Candidate Handbook. A passing score
of 75% or better must be achieved.
This practice examination contains 200 questions organized into six content
domains based on the official CFEI exam blueprint.
DOMAIN BREAKDOWN
Domain I: Fire Science & Chemistry .................... 15% (Questions 1-30)
Domain II: Fire Scene Investigation Methodology ........ 25% (Questions 31-80)
Domain III: Fire Patterns & Damage Analysis ............. 20% (Questions 81-120)
Domain IV: Evidence Collection & Preservation .......... 15% (Questions 121-150)
Domain V: Origin & Cause Determination ................ 15% (Questions 151-180)
Domain VI: Legal & Professional Responsibilities ....... 10% (Questions 181-200)
SECTION I: FIRE SCIENCE & CHEMISTRY
Questions 1-30
Q1. Which of the following is NOT a component of the fire tetrahedron?
A) Fuel
B) Oxygen
C) Heat
D) Carbon dioxide
✅ Answer: D) Carbon dioxide
Rationale: The fire tetrahedron consists of four elements: fuel, oxygen, heat,
and an uninhibited chemical chain reaction. Carbon dioxide is a byproduct of
combustion, not a required component for fire to exist.
1
,Q2. The lowest temperature at which a liquid produces enough vapor to form an
ignitable mixture above its surface is the:
A) Fire point
B) Flash point
C) Autoignition temperature
D) Boiling point
✅ Answer: B) Flash point
Rationale: Flash point is the minimum temperature at which a liquid gives off
sufficient vapor to ignite momentarily when an ignition source is applied. The
fire point (A) is slightly higher and supports sustained burning.
Q3. The process of a solid fuel converting directly to flammable gas by heat is:
A) Sublimation
B) Vaporization
C) Pyrolysis
D) Oxidation
✅ Answer: C) Pyrolysis
Rationale: Pyrolysis is the thermal decomposition of a solid material in an
oxygen-deficient or oxygen-limited atmosphere, producing combustible gases.
Sublimation (A) is a phase change from solid to gas without chemical change.
Q4. Heat release rate (HRR) is defined as:
A) The total heat generated by a fire over its duration
B) The amount of heat energy released per unit time
C) The temperature increase per unit of fuel consumed
D) The rate at which oxygen is consumed
✅ Answer: B) The amount of heat energy released per unit time
Rationale: HRR is measured in kilowatts (kW) or megawatts (MW) and is the
single most important variable in fire hazard assessment, representing the
energy released per second.
Q5. The stoichiometric mixture is:
2
,A) The fuel-rich mixture that produces maximum smoke
B) The ideal fuel-to-oxygen ratio for complete combustion
C) The mixture with the lowest autoignition temperature
D) The fuel-lean mixture that extinguishes the fire
✅ Answer: B) The ideal fuel-to-oxygen ratio for complete combustion
Rationale: At the stoichiometric ratio, there is exactly enough oxygen to
completely oxidize all the fuel, producing only CO2 and H2O with no excess
fuel or oxygen remaining.
Q6. Which class of fire involves energized electrical equipment?
A) Class A
B) Class B
C) Class C
D) Class D
✅ Answer: C) Class C
Rationale: Class C fires involve energized electrical equipment. The primary
hazard is electrical shock, and the extinguishing agent must be non-conductive.
When the power is removed, it becomes a Class A or B fire.
Q7. The temperature at which a liquid's vapor pressure equals atmospheric
pressure is the:
A) Flash point
B) Fire point
C) Boiling point
D) Autoignition temperature
✅ Answer: C) Boiling point
Rationale: Boiling point is the temperature at which the vapor pressure of a
liquid equals the surrounding atmospheric pressure, causing bubbles to form
within the liquid. Flash point is typically lower.
Q8. Which type of heat transfer occurs through electromagnetic waves?
A) Conduction
3
, B) Convection
C) Radiation
D) Induction
✅ Answer: C) Radiation
Rationale: Thermal radiation is the transfer of heat via electromagnetic waves
(infrared, visible light) and does not require a medium. This is how heat
reaches objects not in direct contact with the flame.
Q9. In the context of fire dynamics, "plume" refers to:
A) The column of hot gases and flames above a fire
B) The unburned fuel escaping from the fire
C) The layer of smoke accumulating at the ceiling
D) The pathway of fire spread through a wall
✅ Answer: A) The column of hot gases and flames above a fire
Rationale: The fire plume is the turbulent column of hot gases and flames that
rises above the fire source due to buoyancy. It entrains surrounding air as it
rises toward the ceiling.
Q10. Which of the following statements about autoignition temperature is TRUE?
A) It is always lower than the flash point
B) It is the minimum temperature at which a substance ignites without an
external ignition source
C) It is the temperature at which a liquid boils
D) It is measured only for liquids
✅ Answer: B) It is the minimum temperature at which a substance ignites
without an external ignition source
Rationale: Autoignition temperature (AIT) is the minimum temperature required
to initiate self-sustained combustion independent of an external flame or spark.
It is typically much higher than the flash point.
Q11. The lower flammable limit (LFL) is:
A) The maximum concentration of fuel vapor that will ignite
4
INVESTIGATOR (CFEI) NATIONAL ASSOCIATION OF FIRE
INVESTIGATORS (NAFI) - 2026/2027 NEWEST UPDATE COMPLETE
QUESTIONS AND CORRECT DETAILED ANSWERS WITH RATIONALES|
BRAND NEW VERSION!
EXAM OVERVIEW
The CFEI exam consists of 100 randomly selected questions from a pool maintained by the
National Certification Board. The primary reference source for exam questions is NFPA 921,
with additional references to NFPA 1033 and the NAFI Candidate Handbook. A passing score
of 75% or better must be achieved.
This practice examination contains 200 questions organized into six content
domains based on the official CFEI exam blueprint.
DOMAIN BREAKDOWN
Domain I: Fire Science & Chemistry .................... 15% (Questions 1-30)
Domain II: Fire Scene Investigation Methodology ........ 25% (Questions 31-80)
Domain III: Fire Patterns & Damage Analysis ............. 20% (Questions 81-120)
Domain IV: Evidence Collection & Preservation .......... 15% (Questions 121-150)
Domain V: Origin & Cause Determination ................ 15% (Questions 151-180)
Domain VI: Legal & Professional Responsibilities ....... 10% (Questions 181-200)
SECTION I: FIRE SCIENCE & CHEMISTRY
Questions 1-30
Q1. Which of the following is NOT a component of the fire tetrahedron?
A) Fuel
B) Oxygen
C) Heat
D) Carbon dioxide
✅ Answer: D) Carbon dioxide
Rationale: The fire tetrahedron consists of four elements: fuel, oxygen, heat,
and an uninhibited chemical chain reaction. Carbon dioxide is a byproduct of
combustion, not a required component for fire to exist.
1
,Q2. The lowest temperature at which a liquid produces enough vapor to form an
ignitable mixture above its surface is the:
A) Fire point
B) Flash point
C) Autoignition temperature
D) Boiling point
✅ Answer: B) Flash point
Rationale: Flash point is the minimum temperature at which a liquid gives off
sufficient vapor to ignite momentarily when an ignition source is applied. The
fire point (A) is slightly higher and supports sustained burning.
Q3. The process of a solid fuel converting directly to flammable gas by heat is:
A) Sublimation
B) Vaporization
C) Pyrolysis
D) Oxidation
✅ Answer: C) Pyrolysis
Rationale: Pyrolysis is the thermal decomposition of a solid material in an
oxygen-deficient or oxygen-limited atmosphere, producing combustible gases.
Sublimation (A) is a phase change from solid to gas without chemical change.
Q4. Heat release rate (HRR) is defined as:
A) The total heat generated by a fire over its duration
B) The amount of heat energy released per unit time
C) The temperature increase per unit of fuel consumed
D) The rate at which oxygen is consumed
✅ Answer: B) The amount of heat energy released per unit time
Rationale: HRR is measured in kilowatts (kW) or megawatts (MW) and is the
single most important variable in fire hazard assessment, representing the
energy released per second.
Q5. The stoichiometric mixture is:
2
,A) The fuel-rich mixture that produces maximum smoke
B) The ideal fuel-to-oxygen ratio for complete combustion
C) The mixture with the lowest autoignition temperature
D) The fuel-lean mixture that extinguishes the fire
✅ Answer: B) The ideal fuel-to-oxygen ratio for complete combustion
Rationale: At the stoichiometric ratio, there is exactly enough oxygen to
completely oxidize all the fuel, producing only CO2 and H2O with no excess
fuel or oxygen remaining.
Q6. Which class of fire involves energized electrical equipment?
A) Class A
B) Class B
C) Class C
D) Class D
✅ Answer: C) Class C
Rationale: Class C fires involve energized electrical equipment. The primary
hazard is electrical shock, and the extinguishing agent must be non-conductive.
When the power is removed, it becomes a Class A or B fire.
Q7. The temperature at which a liquid's vapor pressure equals atmospheric
pressure is the:
A) Flash point
B) Fire point
C) Boiling point
D) Autoignition temperature
✅ Answer: C) Boiling point
Rationale: Boiling point is the temperature at which the vapor pressure of a
liquid equals the surrounding atmospheric pressure, causing bubbles to form
within the liquid. Flash point is typically lower.
Q8. Which type of heat transfer occurs through electromagnetic waves?
A) Conduction
3
, B) Convection
C) Radiation
D) Induction
✅ Answer: C) Radiation
Rationale: Thermal radiation is the transfer of heat via electromagnetic waves
(infrared, visible light) and does not require a medium. This is how heat
reaches objects not in direct contact with the flame.
Q9. In the context of fire dynamics, "plume" refers to:
A) The column of hot gases and flames above a fire
B) The unburned fuel escaping from the fire
C) The layer of smoke accumulating at the ceiling
D) The pathway of fire spread through a wall
✅ Answer: A) The column of hot gases and flames above a fire
Rationale: The fire plume is the turbulent column of hot gases and flames that
rises above the fire source due to buoyancy. It entrains surrounding air as it
rises toward the ceiling.
Q10. Which of the following statements about autoignition temperature is TRUE?
A) It is always lower than the flash point
B) It is the minimum temperature at which a substance ignites without an
external ignition source
C) It is the temperature at which a liquid boils
D) It is measured only for liquids
✅ Answer: B) It is the minimum temperature at which a substance ignites
without an external ignition source
Rationale: Autoignition temperature (AIT) is the minimum temperature required
to initiate self-sustained combustion independent of an external flame or spark.
It is typically much higher than the flash point.
Q11. The lower flammable limit (LFL) is:
A) The maximum concentration of fuel vapor that will ignite
4
