Origin & Cause Determination Flashcards
7 cards from real CFI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Origin & Cause Determination flashcards as text
When multiple areas of origin are suspected, what does NFPA 921 say the investigator should do?
Answer: Document and analyze each area separately to determine if multiple independent ignitions occurred
NFPA 921 requires investigators to analyze each suspected area of origin independently to determine whether multiple independent ignitions or a single origin with unusual burn patterns explains the evidence.
Which of the following best describes a 'low burn' indicator and its significance in origin determination?
Answer: Charring or burn damage near floor level that may indicate the fire's lowest point of origin
Low burns refer to fire damage near floor level and may indicate an origin point or accelerant use, though HVAC effects and normal fire behavior must also be considered.
A fire investigator observes that glass windows on one side of a structure are crazed while those on the opposite side are not. What does this most likely indicate?
Answer: The crazed glass side experienced rapid, intense heat consistent with that side being closer to the origin
Crazed glass results from rapid heating and sudden cooling (e.g., from water application), and its location can help investigators determine directional heat exposure relative to the origin.
In cause determination, what is the significance of identifying the 'competent ignition source'?
Answer: It identifies an energy source capable of igniting the first fuel ignited under the conditions present
A competent ignition source must have sufficient energy to ignite the first fuel ignited, and identifying it is a required element of fire cause determination per NFPA 921.
What is the primary reason investigators should document fire patterns before overhaul begins?
Answer: Fire pattern evidence on surfaces is destroyed or obscured during overhaul operations
Overhaul operations disturb, move, and destroy fire pattern evidence on floors, walls, and ceilings, making pre-overhaul documentation critical to preserving origin and cause evidence.
Which scenario best exemplifies 'cause undetermined' as a valid fire cause classification?
Answer: A fire where scientific analysis of available evidence cannot establish a specific cause with reasonable certainty
'Undetermined' is an appropriate classification when the investigator cannot identify the fire cause to a reasonable degree of certainty using available evidence and scientific methodology.
During origin determination, a 'V-pattern' on a wall is found to be very wide at the base. What does this suggest about the fire's behavior?
Answer: The fire had a slow, smoldering growth phase with lower heat release rate
A wide V-pattern base typically indicates a slower-growing fire with a lower heat release rate, while a narrow V-pattern base suggests rapid, intense burning.