Downloaded 30 times
Chapter 14
- 1. Vehicle Fires Chapter 14 © 2009 Delmar, Cengage Learning
- 2. Objectives • Describe thesafety 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 • Studenthad 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.) Figure14-1 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 firesare 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 InitialExamination • 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 InitialExamination (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 Vehicleand Ignitable Fuels • Basic makeup of various vehicles is the same – Framework, wheels, interior, and so forth © 2009 Delmar, Cengage Learning
- 9. Diesel Engines • Dieselengines 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 • Gasolineis 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 • Transmissionfluid, 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 • Mostvehicles 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 • Combinean 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 ofHeat • 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 theVehicle 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 theExterior 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 theExterior 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 • Motorhome 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 muchdifferent 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 thefires 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