Vehicle Fire Investigation
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Introduction
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This presentation will address the trials and tribulations of vehicle fire investigation
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The presenter is Steve Mackaig from Fire Cause Analysis located in California. Don’t hold that against him.
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How’s the National Vehicle Fire
Loss
Picture?
Approximately 285,000 vehicle fires occur per year,
75% of vehicle fires are motor vehicles.
Vehicle fires result in 330 deaths, 1400 injuries and 692 million in
Damage
83 PERCENT ARE CLASSIFIED AS ACCIDENTIAL
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Our Topics for Discussion and
Debate
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Vehicle fire investigation popularity
How is the vehicle fire cause determined?
The field formula of vehicle fire cause
Understanding vehicle systems
Indicators of vehicle system failure
Methodology of a physical fire cause examination
Subrogation
Vehicle arson
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Suggested Reading
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Investigation of Motor Vehicle
Fires, Lee S. Cole
Kirk’s Fire Investigation, John
Dehaan
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NFPA 921, 2011 edition
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Who Enjoys Vehicle Fire
Investigation?
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It appears to be the least popular form of fire cause investigation
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WHY?
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Who is Initially Determining the
Cause of Most Vehicle Fires?
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Private Fire Investigators
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Different scope of responsibility
Uses same process of fire cause determination but long after extinguishment
Limited power to pursue arson
Suspected arsonist may also be client of insurance company
More time and resources for accidental fire causes
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Determining Fire Cause
You Can Choose:
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The wheel of fire origin or
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Flip a coin or
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You can use burn patterns and fire behavior indicators in an organized, safe and scientific approach.
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Landmark Cases such as Daubert have Challenged Fire Experts
Methodology

What is the most internationally excepted Guideline text in Fire
Investigation?
National Fire Protection Association 921
Guide For Fire and Explosion Investigations
2011 Edition Chapter 25 Motor Vehicles

Use a Fire Determination Process that is Considered a Systematic
Approach
The Scientific Method is considered a reliable contemporary Systematic
Approach

Scientific Method
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Recognize The Need ( fire occurs)
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Define The Problem ( requires fire cause
Investigation)
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Collect Data ( facts and indictors)
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Analyze Data ( inductive reasoning)
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Develop an Hypothesis ( cause opinion)
Test Hypothesis ( what didn’t cause the fire )
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Select Final Hypothesis ( Fire Cause Opinion)
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Burning Modern Vehicles Are
Influenced by
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Composites
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Unlimited air supply and wind influence
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Preheated components
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Fuel and oil sources under pressure
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Large amount of plastics and rubber
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The Basic Rule of Thumb in identifying the Area of Origin is:
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The area of origin is identified as the area of most severe damage and the lowest level of severe damage.
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Accidental fires tend to start and develop slowly while arson fires are associated to rapid fire start and spread.
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What is it about modern vehicles that can potentially screw up this basic theory?
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Burn patterns and physical indicators on the vehicle provides the clues of fire cause & origin.
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Unfortunately, the amount of fire damage is proportional to the amount of indicators or clues that remain after the fire.
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Factors that effect your indicators
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Fire fighting activities
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Salvage activities
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Towing activities
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Condition of night time
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Wet surfaces
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Standing water, foam or snow
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Once You Have Identified The
Area of Fire Origin
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Identify all potential ignition sources
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Identify all potential fuel sources
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Systematically rule out unrelated fire causes
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Challenge your own opinion
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Additional Information that can be valuable in determining the fire cause:
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Events prior to the fire
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Vehicle history and use
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Mechanical and recall data research
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Formula For Fire Cause
FUEL
HEAT
EVENT
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The First Step
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Fire typically originates in the area of most severe damage
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Burn patterns on the body reveal direction of fire travel, fire exposure and liquid patterns
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Heat naturally rises and flammable liquids flow to the lower areas.
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Work towards area greatest damage comparing surfaces and the various levels of damage.
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Consider the probabilities
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Where do you think the most common place for a accidental fire to occur is?
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Where do you think arson is the most common?
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Document your investigation as you proceed
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Compare the 5 compartments between each other
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Compare damage within each compartment
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Photograph before and after debris removal
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Recommend using photo procedure that parallels inspection
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Methods of Documentation
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Digital Camera
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Video
 sketching
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Systematically rule out unrelated fire causes
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Potentials include fuel, lubrication, electrical, friction, heat exposure, smoking materials, open flame sources
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Potential follow up issues
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Manufactures defects
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Recent repairs
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Fluid analysis
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Component analysis
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Dealer survey, mechanic inquiry & parts department resources
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Exemplar vehicle
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Let’s examine the 3 elements of fire cause
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First is fuel sources
Gasoline
Diesel fuel
Propane
Power steering fluid
Transmission oil
Gear oil
Anti freeze
Air conditioning refrigerant
Wet cell batteries
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Heat ignition sources
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Engine surface heat
Exhaust system-pipes, manifolds & mufflers
Friction-brake pads, bearings & tires
Electrical system-resistance heating, dead short & energized ground
Smoking materials
Intentional fire setting
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Events
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Was vehicle operating
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System failure potential after parking
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Pre-fire activities and indicators
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Pre-fire conditions such as weather, road grade, towing, turning accessory use
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Fire behaviors
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Fuel system failure is typically rapid flame onset
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Lubricating oil on the exhaust system create lots of white smoke while the vehicle is moving, but no flaming combustion why?
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Electrical fires typically develop from a slow, smoldering state
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Vehicle Component Analysis
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To accurately evaluate accidental fire causes requires a basic understanding of vehicle systems
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It has been my experience that arson determined fires are typically countered with accidental causes so prepare by learning accidental causes.
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Carburetors
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Common in vehicles up to 1975
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Typically in 2 or 4 barrel configuration
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2 to 6 pounds of fuel pressure
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FAILURE POTENTIAL-
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Gasket & seal leakage, improper adjustment
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Backfires
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Fuel Injection
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Fuel is injected into each cylinder by use of a mechanical pump, air pump or electric signal
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Because of normal system pressure, leakage is typically in the form of a spray at 30-40 pounds per square inch.
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Immediate fire, black smoke, rapid spread
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Fuel injection failure potential
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Leakage at the rubber seals
Leakage where fuel distribution rail connects to injectors
Leakage at Schrader valve
Leakage at fuel hose connections
Fuel hose side wall
System pressure spike
Plastic failure from heat, pressure and vibration
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Indicators of fuel system failures
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Severe fire damage in the area of origin
Area of origin houses fuel system components with leakage potential
Origin surfaces are burned cleaned and brightly discolored
Liquid stains and evidence of fuel wash
Fire start described as immediate
Fire described as explosion
Fire occurs during start up
Engine operation is disrupted as fire is discovered
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Lubrication system
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This includes systems that lubricate the engine, transmission and power steering.
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Oil ignites from exposure to exhaust system surface heat
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FAILURE POTENTIAL
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Leaks at gaskets, seals and hoses.
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Indicators of oil leakage related fire
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Area around the origin burned clean with adjacent areas oil stained
Reported white smoke prior to flame discovery
Initially reported as fire under vehicle along with dripping liquid
Fire discovered once vehicle stops moving or up to approximately 10 minutes after parking
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Areas with leakage potential
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Engine-front and rear seals, valve covers, oil filter, oil pan, intake manifold & distributor seal.
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Power steering- hoses, crimp connections, fluid reservoir
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Transmission-rear seal, vent tube and dip stick tube
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Electrical system
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Most types of system failure protected with fuses, relays, fusible links.
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These devises can activate from a short circuit or fire caused heat exposure.
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Types of failure
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Dead short- electrical energy to ground
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Resistance heating-electrical resistance during current flow at weak connection or damaged wire
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Ground fault-ground system becomes energized or ungrounded from poor connection.
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