Vehicle Fire Ignition and Spread
In 2007, there were approximately 260,000 vehicle fires in the United States resulting in almost 1700 injuries, 400 deaths, and $1.4 billion in property damage. The majority of these vehicle fires involve "highway vehicles" which include passenger cars, trucks, buses, and mobile homes but not other vehicles such as farm vehicles, aircraft, trains, and boats. Of these highway vehicle fires, more than 80% occur in passenger vehicles (cars, trucks, vans, sport utility vehicles, etc.). Vehicle fires/car fires tend to peak in July due to high temperatures and increased driving during summer months.
More than half of all highway vehicle fires originate in the engine area or near the wheels. Less than 20% of vehicle fires originate in the passenger compartment, and fewer than 5% of vehicle fires originate in the cargo area or trunk. Under some circumstances, the fuel tank or fuel line can lead to ignition.
Less than 10% of highway vehicle fires are caused by arson. Most vehicle fires are unintentionally caused, often by equipment failure. Mechanical failures (leaks, breaks), electrical short circuits, failure of control systems, and use of incompatible fuels or fluids are all common factors that contribute ignition of vehicle fires.
In more than 50% of fatal highway vehicle fires, gasoline is the first item ignited. Flammable liquids (including gasoline and others) account for approximately 2/3 of all fatalities in vehicle fires. Although collisions cause less than 5% of all highway vehicle fires, they are responsible for approximately 60% of all highway fire fatalities.
Flammability of interior materials in motor vehicles flammability is regulated by the US Federal Code of Regulations, Title 49, Chapter 5, Section 571, Subsection 302 (Federal Motor Vehicle Safety Standard 302). FMVSS 302 is an ad hoc flame spread test that applies to cars, trucks, and buses less than 10,000 pounds. All interior materials (upholstery, seat cushions, carpet/flooring, sun visors, headliners, seat belts, trim, etc.) located within 1/2 inch of the of the passenger compartment airspace must pass FMVSS 302. A material passes FMVSS 302 if flame spreads across its surface at a rate of fewer than 4 inches per minute, otherwise, it fails.
When investigating vehicle fires, the following questions are frequently asked:
- Where did the vehicle fire originate?
- What are possible ignition sources?
- What was the first item ignited?
- How quickly did the fire spread (through the engine compartment, into the passenger compartment, through the passenger compartment, etc.)
- When would conditions have become untenable?
- When did windows break?
- How would the vehicle fire have been different if different materials were used?
These questions and others can be answered by our fire experts.