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Free IAAI CFI Practice Questions

10 free, exam-style Certified Fire Investigator (IAAI CFI) practice questions with answers and explanations. No signup required. Work through them below, then take the full free IAAI CFI practice test to study every exam domain.

These 10 free IAAI CFI questions are organized by exam domain, so you can see how each part of the Certified Fire Investigator blueprint is tested. Reveal the answer and explanation under each question.

Domain 1: Preparation

Question 1

A 1,500-watt space heater is connected to a standard 120-volt branch circuit. Using P = I × V, approximately how much current does it draw?

  1. 12.5 amps
  2. 0.08 amps
  3. 1,620 amps
  4. 180 amps
Show answer & explanation

Correct answer: A - 12.5 amps

Question 2

A fire in a closed room appears to diminish and nearly self-extinguish, then sharply intensifies the moment firefighters force open the door. This behavior is most characteristic of a fire that was:

  1. Ventilation-controlled before the door was opened
  2. Fuel-controlled throughout its entire development
  3. Ignited by a delayed-action chemical accelerant device
  4. Still in its early incipient stage when the door opened
Show answer & explanation

Correct answer: A - Ventilation-controlled before the door was opened

Domain 2: Scene Examination

Question 3

Investigators find irregular, sharply bordered burn patterns on the floor of a room that reached full involvement (post-flashover). Standing alone, what do these patterns establish?

  1. That an ignitable liquid was deliberately poured on the floor
  2. Nothing conclusive; they require laboratory corroboration
  3. That the fire originated at floor level rather than higher up
  4. That the fire was incendiary and not accidental in nature
Show answer & explanation

Correct answer: B - Nothing conclusive; they require laboratory corroboration

Question 4

An investigator observes a network of short, web-like cracks (crazing) in window glass. According to current fire investigation science, crazed glass is most reliably associated with:

  1. An exceptionally fast, hot fire
  2. Rapid cooling, such as from a hose stream
  3. The presence of an ignitable liquid accelerant
  4. A backdraft event in the compartment
Show answer & explanation

Correct answer: B - Rapid cooling, such as from a hose stream

Domain 3: Documenting the Scene

Question 5

An investigator eliminates every accidental cause in a room and, with no accidental explanation remaining, classifies the fire as incendiary - yet identifies no ignition source, first fuel, or ignition sequence. This reasoning is improper because it relies on:

  1. Deductive testing of a hypothesis
  2. Inductive analysis of the data
  3. The negative corpus (elimination without supporting data)
  4. A premature undetermined classification
Show answer & explanation

Correct answer: C - The negative corpus (elimination without supporting data)

Domain 5: Interviewing

Question 6

An investigator collects fire debris suspected of containing ignitable liquid residue. To preserve the volatile evidence for laboratory analysis, the sample should be packaged in:

  1. An ordinary polyethylene plastic zip-top freezer bag
  2. A sealed brown paper evidence bag of the standard type
  3. An open cardboard box so the wet sample can dry out
  4. A clean, unlined metal can or vapor-tight container
Show answer & explanation

Correct answer: D - A clean, unlined metal can or vapor-tight container

Domain 6: Post-Incident Investigation

Question 7

Examining wiring, an investigator finds a copper conductor with a smooth, rounded bead and a sharp line of demarcation between affected and unaffected metal. Standing alone, what does this arc bead establish?

  1. That the building's electrical system was the cause of the fire
  2. That the conductor melted gradually from external fire heat alone
  3. That an ignitable liquid accelerant was present nearby at ignition
  4. That electrical activity occurred there, but not that it caused the fire
Show answer & explanation

Correct answer: D - That electrical activity occurred there, but not that it caused the fire

More IAAI CFI practice questions

Question 8

At the autopsy of a victim recovered from a structure fire, the medical examiner documents soot within the trachea and lower airway. This finding most strongly indicates that the victim:

  1. Was already deceased before the fire reached the body
  2. Sustained only postmortem thermal injury after death
  3. Has a heat-induced skin split that was mistaken for trauma
  4. Was alive and breathing during the fire
Show answer & explanation

Correct answer: D - Was alive and breathing during the fire

Question 9

A natural-gas leak has filled a room to a concentration well above the gas's upper explosive limit (UEL). At this exact moment, the atmosphere is:

  1. Highly explosive and will ignite from the smallest spark
  2. Below the lower explosive limit, and therefore entirely safe
  3. Too rich to ignite, but may become ignitable as it dilutes
  4. Permanently incapable of ignition under any condition
Show answer & explanation

Correct answer: C - Too rich to ignite, but may become ignitable as it dilutes

Question 10

In a jurisdiction that follows the Frye standard, the admissibility of scientific expert testimony turns primarily on whether the underlying technique or theory:

  1. Has a known or potential rate of error in application
  2. Has been published and subjected to peer review
  3. Has gained general acceptance in the relevant field
  4. Is personally endorsed by the trial judge as gatekeeper
Show answer & explanation

Correct answer: C - Has gained general acceptance in the relevant field

The rest of the IAAI CFI blueprint

The IAAI CFI exam also covers these domains. Drill them in the full free practice test:

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