IFSTA Chapter 24 Exam Questions & Verified Answers
| Fire Origin & Cause Determination | Essentials of Fire
Fighting 7th Edition | Firefighter I & II Certification
Prep | 100% Correct
Time: 80 minutes. Select the BEST answer. All questions are based on IFSTA Chapter 24
and NFPA 921.
1. The first-arriving company officer observes a rapidly growing fire on the first floor
of a single-family dwelling. After extinguishment, which initial action best
supports origin-and-cause determination?
A. Begin overhaul immediately to expose hidden fire
B. *Secure the scene and request a qualified fire investigator
C. Remove all contents to the front yard for inspection
D. Turn off all utilities and leave the building
Rationale: NFPA 921 (2024 ed.) 4.2.1 and IFSTA Ch. 24 both stress scene
security as the first priority to preserve evidence; premature overhaul or moving
objects destroys patterns.
2. While overhauling, a firefighter discovers a melted plastic container with an odor
similar to gasoline. The correct procedure is to:
A. Dispose of the container in the structure debris dumpster
B. *Leave the item in place, protect it from further damage, and notify the
investigator
C. Sniff the contents to confirm odor
D. Seal the item in a plastic evidence bag immediately
Rationale: NFPA 921 15.1.2: potential evidence must be preserved in situ until
documented; plastic bags can evaporate ignitable liquids; investigator handles
sampling.
3. Which burn pattern most clearly indicates a low, slow-burning fire originating at
floor level?
A. V-patterns on the upper half of a doorway
, B. Clean burn on the ceiling above a sofa
C. *Charring and loss of wood flooring in an oval area with surrounding shallow
char
D. Light soot on window glass
Rationale: Oval/circular floor-level char with decreasing depth outward is classic
“pour” pattern (NFPA 921 6.3.7.2); V-patterns indicate vertical spread; ceiling
patterns show plume rise.
4. A firefighter observes shiny, spattered metal on a brass door lock. This is MOST
consistent with:
A. Water hammer effect
B. *Melting due to intense localized heat (possible ignitable liquid)
C. Failure of fire hose coupling
D. Normal oxidation
Rationale: Low-melting-point metals (brass, aluminum) melted suggest
temperatures >1,650 °F (900 °C) localized, often associated with ignitable liquids
(NFPA 921 6.10.4).
5. The point of origin is BEST defined as the:
A. Room with the greatest fire damage
B. Location where the first fuel package ignited
C. *Location where the ignition source and first fuel came together
D. Area where flames vented from a window
Rationale: IFSTA Ch. 24 defines point of origin as the smallest area where heat,
fuel, and oxygen first combined to produce sustained combustion (NFPA 921
3.3.120).
6. A firefighter sees a trail of burned paper fragments leading from the living room
to the kitchen. This pattern is MOST indicative of:
A. Flashover
B. *Trail of an ignitable liquid
C. Backdraft
D. Short-circuit
Rationale: Linear, discontinuous burn pattern is termed a “trail,” commonly
associated with poured ignitable liquids (NFPA 921 6.3.7.3).
7. Which statement about spalling of concrete is TRUE?
A. It always indicates presence of ignitable liquids
B. *It can result from rapid thermal expansion or chemical reactions, not just
liquids
C. It proves an incendiary fire
D. It is irrelevant to cause determination
| Fire Origin & Cause Determination | Essentials of Fire
Fighting 7th Edition | Firefighter I & II Certification
Prep | 100% Correct
Time: 80 minutes. Select the BEST answer. All questions are based on IFSTA Chapter 24
and NFPA 921.
1. The first-arriving company officer observes a rapidly growing fire on the first floor
of a single-family dwelling. After extinguishment, which initial action best
supports origin-and-cause determination?
A. Begin overhaul immediately to expose hidden fire
B. *Secure the scene and request a qualified fire investigator
C. Remove all contents to the front yard for inspection
D. Turn off all utilities and leave the building
Rationale: NFPA 921 (2024 ed.) 4.2.1 and IFSTA Ch. 24 both stress scene
security as the first priority to preserve evidence; premature overhaul or moving
objects destroys patterns.
2. While overhauling, a firefighter discovers a melted plastic container with an odor
similar to gasoline. The correct procedure is to:
A. Dispose of the container in the structure debris dumpster
B. *Leave the item in place, protect it from further damage, and notify the
investigator
C. Sniff the contents to confirm odor
D. Seal the item in a plastic evidence bag immediately
Rationale: NFPA 921 15.1.2: potential evidence must be preserved in situ until
documented; plastic bags can evaporate ignitable liquids; investigator handles
sampling.
3. Which burn pattern most clearly indicates a low, slow-burning fire originating at
floor level?
A. V-patterns on the upper half of a doorway
, B. Clean burn on the ceiling above a sofa
C. *Charring and loss of wood flooring in an oval area with surrounding shallow
char
D. Light soot on window glass
Rationale: Oval/circular floor-level char with decreasing depth outward is classic
“pour” pattern (NFPA 921 6.3.7.2); V-patterns indicate vertical spread; ceiling
patterns show plume rise.
4. A firefighter observes shiny, spattered metal on a brass door lock. This is MOST
consistent with:
A. Water hammer effect
B. *Melting due to intense localized heat (possible ignitable liquid)
C. Failure of fire hose coupling
D. Normal oxidation
Rationale: Low-melting-point metals (brass, aluminum) melted suggest
temperatures >1,650 °F (900 °C) localized, often associated with ignitable liquids
(NFPA 921 6.10.4).
5. The point of origin is BEST defined as the:
A. Room with the greatest fire damage
B. Location where the first fuel package ignited
C. *Location where the ignition source and first fuel came together
D. Area where flames vented from a window
Rationale: IFSTA Ch. 24 defines point of origin as the smallest area where heat,
fuel, and oxygen first combined to produce sustained combustion (NFPA 921
3.3.120).
6. A firefighter sees a trail of burned paper fragments leading from the living room
to the kitchen. This pattern is MOST indicative of:
A. Flashover
B. *Trail of an ignitable liquid
C. Backdraft
D. Short-circuit
Rationale: Linear, discontinuous burn pattern is termed a “trail,” commonly
associated with poured ignitable liquids (NFPA 921 6.3.7.3).
7. Which statement about spalling of concrete is TRUE?
A. It always indicates presence of ignitable liquids
B. *It can result from rapid thermal expansion or chemical reactions, not just
liquids
C. It proves an incendiary fire
D. It is irrelevant to cause determination
