1. Vehicle Fires
Chapter 14
© 2009 Delmar, Cengage Learning

2. Objectives
• Describe the safety precautions that must be
taken before starting the investigation
• Describe the fuel and electrical systems of most
common vehicles
• Describe the potential heat sources and fuels
available in most vehicles today
• Describe the potential for arson and which
indicators may point to an incendiary nature of
the fire
© 2009 Delmar, Cengage Learning

3. Case Study
• Student had no feeling below arms
• Family obtained used car that could be operated
by hand controls
• Mother noticed burning smell when son returned
from school and found that he suffered burns to
his back
• Investigation of vehicle found seat heater had
malfunctioned, causing burns
© 2009 Delmar, Cengage Learning

4. Case Study (cont’d.)
Figure 14-1 Front seat Figure 14-2 The heating
driver’s side showing element that was located
heat damage of seat directly behind fabric on the
fabric. seat’s upright.
© 2009 Delmar, Cengage Learning

5. Introduction
• Vehicle fires are some of the most confusing
fires to work
• Investigators need to do fire scene
reconstruction
– Work the scene from the least damage to the most
damage
• Passenger vehicle today is an extremely
complex device
• 278,000 vehicle fires occurred in 2006
© 2009 Delmar, Cengage Learning

6. Safety and Initial Examination
• All precautions should be taken to protect
yourself and others from injury
• Materials in modern vehicles contain numerous
toxic fumes that are released from burning
components
– Range from hydrogen cyanide to carbon monoxide
– Off-gassing: refers to vapors or gases that were
absorbed by fabric, carpet, and so forth during a fire
and then released after the fire was extinguished
© 2009 Delmar, Cengage Learning

7. Safety and Initial Examination
(cont’d.)
• First responder investigator should not take for
granted that the initial fire crews have secured
the vehicle
• Airbag deployment is a huge area of concern
– Bags can inflate in 1/20th of a second
• Not recommended to crawl under the vehicle
• Always be aware of sharp edges and broken
glass
– Wear protective equipment at all times
© 2009 Delmar, Cengage Learning

8. Type of Vehicle and Ignitable Fuels
• Basic makeup of various vehicles is the same
– Framework, wheels, interior, and so forth
© 2009 Delmar, Cengage Learning

9. Diesel Engines
• Diesel engines operate on a compressed
combustion chamber
• Diesel fuel is a combustible liquid with a flash
point above 100° F
• Fuel is stored in a sealed tank and is pumped
from a fuel pump through lines and filters
• Failure of the system at any given point may be
a possible point of fuel release in some vehicle
fires
© 2009 Delmar, Cengage Learning

10. Gasoline Engines
• Gasoline is more volatile and has a lower
ignition temperature
– Causes concern about it being the first fuel ignited
• Gasoline engines operate on flammable liquids
that have a flash point of less than 100°F
– Lack of maintenance or worn and loose parts can
cause the fuel to be sprayed
• Possible cause for the spread of the fire in the event it
came into contact with an ignition source
© 2009 Delmar, Cengage Learning

11. Other Liquids
• Transmission fluid, windshield washer solvents,
ethylene glycol, motor oil, brake fluids, and
other hydraulic fluids
– May ignite under extreme conditions, either
contributing to or causing a fire
© 2009 Delmar, Cengage Learning

12. Hot Surfaces
• Manifold, catalytic converter, and exhaust pipe
operate at sufficient temperatures to ignite a
wide range of fuels
• Leaking brake fluid is most often the first fuel
ignited when it leaks onto a hot surface
• Gasoline will not usually ignite when sprayed
onto a hot surface
– Many variables such as ventilation or humidity can
influence this
© 2009 Delmar, Cengage Learning

13. Electrical Systems
• Most vehicles operate on a 12-volt direct current
(DC) system
– Secondary wiring can come into play in fires from
wear and tear and misuse
– Resistance heating can cause the insulation around
the wire to break down or melt
• Hybrids bring a whole new realm to the
investigation of vehicle fires
– Voltage in hybrid vehicles can reach more than 300
volts of alternating current (AC)
© 2009 Delmar, Cengage Learning

14. Hybrid Vehicles
• Combine an internal combustion gasoline
engine with an electric, battery-powered motor
• Contain a high-voltage NI-MH battery pack
• In a series hybrid, the gasoline engine will
automatically stop and start
• In a parallel system, the electric motor runs in
conjunction with the gasoline engine
• If the vehicle is partially or more submerged, do
not touch any high-voltage components
© 2009 Delmar, Cengage Learning

15. Other Forms of Heat
• Vehicle’s heater, fans, and wires attached need
to be looked at
• Properly operating catalytic converter, located
on the underside of the vehicle, can reach
temperatures of more than 700° F
• Turbo chargers create tremendous amounts of
heat and may be a source of ignition
• Smoking-related incidents can be difficult to find
© 2009 Delmar, Cengage Learning

16. How Did the Vehicle Burn and
Why?
• If the vehicle was kept in clean and running
condition and there is a fire, it may have been
arson
– For the purpose of insurance fraud
• Scene first needs to be photographed from all
sides
• Photos of the area from the vehicle looking
outward need to be taken
– Particularly important when a stolen vehicle is found
© 2009 Delmar, Cengage Learning

17. What Does the Exterior of the
Vehicle Tell You?
• Extent of damage may show direction of fire
travel
• Burn marks or demarcation lines may show path
of travel
• Patterns left behind will show the direction from
where the fire began
• Fire burns typically up and out
– V pattern as in structure fire
© 2009 Delmar, Cengage Learning

18. What Does the Exterior of the
Vehicle Tell You? (cont’d.)
• VIN contains information about the vehicle, such
as year, make, model, engine, and paint color
• One interesting facet to look at is the vehicle’s
glass
– Fire will cause long cracks on the front windshield
• Look at the tires remaining on the vehicle
– May show direction of flame
© 2009 Delmar, Cengage Learning

19. Inside the Vehicle
• Look at the glove box
• Did the owner leave the keys in the vehicle?
• Most of the interior of the vehicle is combustible
– Composed of plastics or fabric
• Hood will show burn patterns from the heat and
flame impingement if the fire was in the engine
compartment
© 2009 Delmar, Cengage Learning

20. Motor Homes
• Motor home contains components of a vehicle
combined with the combustibles and heat
source of a structure
• Motor homes are unusual and must be
investigated with care
– May contain liquid propane gas for heat and fuel for
the cooking equipment
– May have a built-in generator that may use a
flammable or combustible liquid
© 2009 Delmar, Cengage Learning

21. Boats
• Not much different from a vehicle or a motor
home
• Gasoline can collect in lowest part of hull
• Unique situations in boat fires
– Possibility that the boat sank
• With inboard motors, you should look into the
engine compartment
• Area where the boat was moored should be
closely examined
© 2009 Delmar, Cengage Learning

22. Summary
• Work the fires from the exterior to the interior
and from the least damaged to most damaged
• Scene needs to be documented and
photographed on all sides
• Investigator needs to sift debris to find evidence
that will aid in using a scientific methodology
• Both motor homes and boats have the same
characteristics as other motorized vehicles
© 2009 Delmar, Cengage Learning