Fire Science & Chemistry
Not publishedof exam
Fire Behavior & Dynamics
Not publishedof exam
Explosion Investigation
Not publishedof exam
DeflagrationDetonationBLEVEFlammable Range
Origin Determination & Fire Patterns
Not publishedof exam
Fire PatternsFire EffectsOrigin AnalysisScene Examination
Cause Determination
Not publishedof exam
Cause ClassificationsIgnition SourcesIncendiary IndicatorsNegative Corpus
Evidence Collection & Lab Analysis
Not publishedof exam
Evidence HandlingChain of CustodyLab AnalysisGC-MS
Electrical Fire Investigation
Not publishedof exam
Electrical FailuresArc MappingGFCIPhotovoltaic Hazards
Methodology, Legal & Documentation
Not publishedof exam
Scientific MethodLegal StandardsDocumentationConfirmation Bias
Building Systems & Construction
Not publishedof exam
Quick Facts
- Exam
- CFEI
- Credential
- Fire & Explosion Investigator
- Questions
- 100 MC/True-False
- Time
- 2 hours
- Pass score
- 75% (75 of 100)
- Format
- Closed-book
- Level
- Professional certification
- Primary reference
- NFPA 921
Fire Tetrahedron
Fuel + Heat + Oxygen + Chain Reaction
Fuel: combustible materialHeat: ignition energyOxygen: the oxidizerChain reaction: sustains burning
Flash Point vs Autoignition Temperature
Flash point
- Needs ignition source
- Lower temperature
Autoignition temp
- No spark needed
- Higher temperature
External spark vs spontaneous
Heat Transfer Mode Picker
- Direct object-to-object contact→Conduction
- Hot gas or fluid movement→Convection
- No contact, electromagnetic waves→Radiation
- Fire spreading to nearby exposures→Radiant heat transfer
Fire Tetrahedron & Heat Transfer
- Fuel
- Combustible material
- Heat
- Ignition energy source
- Oxygen
- Oxidizer, roughly 16%+
- Chain reaction
- Self-sustaining combustion process
- Conduction
- Direct contact heat transfer
- Convection
- Hot gas or fluid movement
- Radiation
- EM waves, no contact
Combustion Chemistry & Byproducts
- Pyrolysis
- Heat decomposes solid fuel
- Flash point
- Lowest vapor-ignites temperature
- Autoignition temperature
- Ignites without external spark
- Stoichiometric mixture
- Ideal fuel-to-air ratio
- Heat of combustion
- Energy released per mass
- Fire load
- Combustibles per floor area
- Carbon monoxide (CO)
- Incomplete combustion, most toxic
- Hydrogen chloride (HCl)
- PVC burning, corrosive gas
Compartment Fire Stages
Ignition, growth, flashover, fully developed, decay
Order: I-G-F-FD-DFlashover near 1,000°FDecay: fuel or O2 gone
Flashover vs Backdraft
Flashover
- Radiant heat feedback
- Full room involvement
Backdraft
- Sudden oxygen introduction
- Ventilation-limited fire
Heat trigger vs oxygen trigger
Compartment Fire Stages
- Ignition
- Combustion begins
- Growth
- Fire size increasing
- Flashover
- ~1,000°F, full room involvement
- Fully developed
- Peak burning rate
- Decay
- Fuel or oxygen depleted
- Backdraft
- Sudden oxygen, explosive ignition
Fire Dynamics Variables
- Heat release rate (HRR)
- kW, key fire variable
- Thermal layering
- Hot gases stratify at ceiling
- Ventilation-controlled
- Oxygen-limited burning rate
- Fuel-controlled
- Fuel-limited burning rate
- Growth rate (alpha)
- kW/s², fire growth speed
Deflagration vs Detonation
Deflagration
- Subsonic propagation
- Most fuel-air explosions
Detonation
- Supersonic shock front
- High explosives
Speed of propagation
Explosion & Flammable Range
- Deflagration
- Subsonic flame propagation
- Detonation
- Supersonic shock front
- BLEVE
- Pressurized vessel ruptures, boils
- LEL
- Minimum ignitable concentration
- UEL
- Maximum ignitable concentration
- Propane range
- 2.1% to 9.5%
- Methane range
- 5% to 15%
Area of Origin vs Point of Origin
Area of origin
- General location
- Room or zone
Point of origin
- Exact spot
- Fuel meets heat source
General vs specific
Fire Pattern Interpretation
- V-shape burn on wall→Trace plume to base
- Irregular pattern on floor→Send sample to lab
- Shiny large char blisters→Rapid heat, not proof
- Multiple unconnected fire origins→Strong incendiary indicator
- Pattern alone, no lab data→Insufficient for cause
Fire Pattern Types
- V-pattern
- Plume rises from base
- Pour pattern
- Possible liquid, confirm via lab
- Clean burn
- Soot burned off, intense heat
- Demarcation line
- Boundary of fire damage
- Alligator char
- Rapid, intense heat exposure
- Trailer
- Connects fuel packages, arson sign
Fire Effects & Origin Analysis
- Char depth
- Relative burn duration/intensity
- Calcination
- Gypsum loses bound water
- Spalling
- Concrete surface flaking, heat
- Glass fracture
- Shows force direction, timing
- Arc mapping
- Plots arcs, shows spread
- Origin matrix
- Systematic data evaluation tool
- Area of origin
- General fire start location
- Point of origin
- Exact ignition location
- Top-down excavation
- Remove debris layer by layer
- Seat of fire
- Deepest char, not always origin
Four Cause Classifications
Accidental, natural, incendiary, undetermined, never negligent
No 'negligent' category existsUndetermined is validNegative corpus is invalid
Accidental vs Undetermined
Accidental
- No deliberate act
- Cause identified
Undetermined
- Cause unknown
- Insufficient evidence
Known cause vs no cause
Fire Cause Classification Logic
- All accidental causes ruled out→Still need positive evidence(Avoid negative corpus)
- Deliberate act proven→Classify as incendiary
- Lightning or natural event proven→Classify as natural
- No deliberate or natural cause→Classify as accidental
- Insufficient certainty either way→Classify as undetermined
Fire Cause Classifications
- Accidental
- No deliberate human act
- Natural
- Lightning or natural event
- Incendiary
- Deliberately set fire
- Undetermined
- Insufficient certainty either way
- Negative corpus
- Invalid: elimination alone insufficient
Ignition & Incendiary Indicators
- Competent ignition source
- Sufficient heat and energy
- First fuel ignited
- Material first set aflame
- Incendiary device
- Built to start fire
- Multiple origins
- Strong incendiary indicator
- Total burning
- Can occur without accelerant
Evidence Handling & Custody
- Chain of custody
- Document all evidence handlers
- Unlined metal cans
- Airtight ignitable liquid containers
- Comparison samples
- Unburned baseline material
- Spoliation
- Evidence destroyed or altered
- Scene safety
- Always the first priority
Lab Analysis Standards
- GC-MS
- Identifies ignitable liquid residues
- ASTM E1618
- GC-MS identification test method
- ASTM E1412
- Passive charcoal headspace extraction
- ASTM E1413
- Dynamic headspace extraction method
- Passive headspace
- Charcoal strip absorbs vapors
Electrical Failure Types
- Short circuit
- Current takes unintended path
- Overcurrent
- Exceeds conductor rating
- Ground fault
- Current flows to ground
- High-resistance connection
- Loose joint, glowing heat
- Arc bead
- Melted copper, arc evidence
Electrical Safety & Systems
- GFCI
- Trips at ~5 milliamps
- Circuit breaker
- Overcurrent protection device
- PV systems
- Energized whenever exposed to light
- Overload
- Excess current generates heat
NFPA 921 Scientific Method
Recognize, define, collect, analyze, hypothesize, test, select
Seven steps in orderTest before selectingReject unsupported hypotheses
Daubert vs Frye
Daubert
- Federal standard
- Reliability plus methodology test
Frye
- Some state courts
- General acceptance test
Federal vs some states
Warrantless Entry Timing Rules
- During active fire suppression→No warrant needed
- Reasonable time after extinguishment→No warrant needed
- Investigators already left scene→Need consent or warrant
- Criminal evidence beyond origin/cause→Need criminal search warrant
Scientific Method Steps
- Recognize need
- Step 1: identify problem exists
- Define problem
- Step 2: scope the question
- Collect data
- Step 3: gather evidence
- Analyze data
- Step 4: evaluate evidence
- Develop hypothesis
- Step 5: propose explanation
- Test hypothesis
- Step 6: check against data
- Select final hypothesis
- Step 7: accept supported theory
Legal Standards & Cases
- Michigan v. Tyler
- Warrantless post-fire entry allowed
- Michigan v. Clifford
- Re-entry needs consent or warrant
- Daubert standard
- Federal expert testimony test
- Frye standard
- General scientific acceptance test
- Preponderance
- Civil standard, more likely than not
- Beyond reasonable doubt
- Criminal case standard
Documentation & Bias
- Photo sequence
- Overall scene to close-up
- Scale reference
- Shows true evidence size
- Baseline method
- Measure along fixed reference line
- Scene diagram
- Scaled spatial evidence layout
- NFIRS
- National fire incident database
- Confirmation bias
- Favoring pre-existing conclusion
Fire Wall vs Fire Barrier
Fire wall
- Structural element
- Between buildings/sections
Fire barrier
- Non-structural element
- Within one building
Structural vs non-structural
Fire Protection Systems
- Fusible link
- Melts, releases sprinkler water
- Ionization detector
- Faster on flaming fires
- Photoelectric detector
- Faster on smoldering fires
- Fire damper
- Closes duct when heated
- Central station
- 24/7 off-site monitoring
Construction Types & Barriers
- Type I
- Fire-resistive, non-combustible
- Type III
- Ordinary construction
- Type IV
- Heavy timber construction
- Type V
- Wood frame construction
- Fire wall
- Structural, between buildings
- Fire barrier
- Non-structural, within one building
Common Traps
Patterns ≠ Proof of Accelerant
V-pattern alone is insufficient ≠ Must confirm via lab test
Negative Corpus ≠ Valid Method
Elimination isn't affirmative proof ≠ NFPA 921 explicitly rejects this
Seat of Fire ≠ Origin
Deepest char can mislead ≠ Ventilation affects burn location
Total Burning ≠ Accelerant Proof
Ventilated fires burn completely ≠ Ordinary combustibles alone suffice
Frye ≠ Daubert Standard
Different jurisdictions apply each ≠ Don't assume they're identical
Alligator Char ≠ Accelerant Proof
Shows intense heat only ≠ Any well-ventilated fire produces it
Last Minute
- 1.100 questions, 2-hour time limit
- 2.75% passing score required
- 3.Closed-book: no outside references allowed
- 4.NFPA 921 is primary reference
- 5.Scene safety is always first
- 6.Use scientific method, test hypotheses
- 7.Avoid negative corpus reasoning
- 8.Four causes exist, no 'negligent'
- 9.V-patterns alone don't prove accelerant
- 10.Chain of custody must be unbroken
- 11.Undetermined is a valid conclusion
- 12.Match confidence level to evidence
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