Managing Vehicle Fires Safely

BY DOUG LEIHBACHER

Vehicle fires remain an integral part of fire department responses. According to the U.S. Fire Administration’s October 2008 Topical Report, “Highway vehicle fires account for approximately one-sixth of all fire responses annually.” Considered a “routine” response by many firefighters, these fires account for the following:

  • approximately 400 civilian deaths annually;
  • 1,700 civilian and 1,100 firefighter injuries; and
  • $1.3 billion in property damage each year.

Although there has been a downward trend in the number of vehicle fires over the past decade—from 381,000 in 1998 to 258,000 in 2007—the hazards associated with these incidents have remained elevated as vehicles have become more technologically sophisticated. Since they infrequently pose an exposure threat (unless they are next to a building or are in a garage), many departments assign only a single engine company to respond to these incidents. Some engines use the booster or “red” line to extinguish vehicle fires. These practices may underestimate the potential of these incidents.

A vehicle fire can generate toxic smoke, launch projectiles, and generate heat upward of 1,500°F. Use a flow of at least 125 gallons per minute to control these incidents. The sooner the fire goes out, the safer the incident, and there is little reason to be concerned with water damage. In addition to extinguishment, there are many ancillary tasks that must be completed, such as scene safety, traffic control, forcible entry, vehicle stabilization, overhaul, fire cause determination, and hazard and spill control. For these reasons, it is important not to underestimate these incidents from a staffing and a tactical standpoint.

RISK VS. BENEFIT

Although vehicle fires remain an important part of firefighting duties, handle these incidents in a cautious, safe manner commensurate with a size-up and risk assessment. When sizing up a vehicle fire, begin by sizing up the scene. Make sure all traffic is stopped, no wires are down, and any fuel spills are controlled. Once you have assessed the scene, size up the vehicle fire. Is there a life hazard (someone trapped in the vehicle)? In what stage is the fire—incipient, smoldering, or open flame? Are the windows vented? Which compartment is on fire—the engine compartment, the passenger compartment, or the trunk? Is more than one compartment involved?

The potential hazards vary with the compartment involved.The more compartments involved, the greater the hazard. Statistical analysis indicates that almost two-thirds of vehicle fires begin in the engine compartment and most of the remaining fires originate in the passenger compartment. Only about three percent start in the trunk. Most engine compartment fires are mechanical in origin. A higher percentage of fires that originate in the trunk and passenger compartment are electrical or incendiary.


(1) Firefighters position a hoseline at a 45° angle and prepare to extinguish a fully involved vehicle after an auto collided with a pole. (Photos 1-3 by Keith Muratori, firegroundimages.com/; photos 4-8 by author.)

Fires originating in one compartment can quickly spread to others, depending on wind direction, fuel load, and other factors. The term firewall is commonly used to refer to the barrier between a vehicle’s passenger and engine compartments. Similar to a ship’s bulkhead, a vehicle’s firewall is metallic and fitted to seal off the engine compartment. As many firefighters can attest, however, vehicle firewalls may briefly forestall but do not prevent fire from spreading from one compartment to the other. Vehicle firewalls are not time rated like fire walls in buildings. Fire can spread by means of voids in the fire wall through which wiring and air vents pass. Fire also transmits by means of conduction through the metal wall to ignite combustible liners, insulation, and wires in contact with it on the passenger compartment side. Fires generally spread rather quickly through the firewall from the engine compartment to the passenger compartment and more slowly in the opposite direction.

Whenever fire enters another compartment, consider the potential hazards associated with that compartment. A fire in the engine compartment may impinge on hood struts, magnesium engine parts, the battery, and energy-absorbing bumpers. A passenger compartment fire may heat air bag-inflating canisters and seat belt tensioners and generate thick, toxic smoke. Once limited to the steering column and dashboard, air bag inflators are now found throughout the passenger compartment from the seats to the A, B, and C posts. A fire in the trunk puts heat close to the gas tank and the cargo in the trunk, which, once heated, is often very hazardous. Gasoline cans, aerosols, and 20-pound propane cylinders are frequently transported in trunks and can greatly increase the hazard of a vehicle fire. The driver can provide important size-up information about the trunk’s contents.


(2) The apparatus is blocking the roadway to provide a traffic-free work zone.

Whenever firefighters conduct a risk assessment, life is always the first priority. Protecting property is the secondary priority, but there is no property value to save at a vehicle fire that has developed beyond the incipient stage. Unlike structure fires where carefully placed hoselines can save valuable property, in the case of vehicle fires the postfire property value is virtually nil. Burned cars are not rebuilt; they are sold for scrap, so there is no reason to aggressively attack a burning vehicle unless a victim is trapped inside. Save aggressive fire attack for occupied structure fires. Tackle common vehicle fires safely and conservatively.

APPARATUS PLACEMENT

Safe procedures begin when the apparatus approaches the scene. The engineer or chauffer should slow down when arriving at a vehicle fire. Consider that pedestrians, good Samaritans, victims, civilians directing traffic, downed wires, and fuel spills are in and around the area, and determine the best position for the apparatus (visible, upwind, and uphill). Allowing enough time to slow the vehicle is especially important when approaching from a high-speed thoroughfare, where additional time and distance are needed to slow the vehicle to a halt before entering the fire zone.

When positioning the apparatus, remember not to encroach on the burning vehicle. Parking the apparatus at least 100 feet from the fire provides a margin of safety should a fuel line rupture or something blow up in the trunk. Moreover, the apparatus should be oriented so that it shields firefighters, including the pump operator, from oncoming traffic. This often means parking the apparatus on a diagonal across two traffic lanes or one lane and the shoulder, thereby protecting firefighters from oncoming traffic and creating a safe work zone. Depending on traffic flow, wise vehicle positioning may mean stopping before the fire or passing it and parking beyond it. Once the vehicle draws to a halt, members should look out before exiting the vehicle and stepping down onto the pavement.

The following procedures and precautions make operations at the scene safer:

  • Wear full protective gear with reflective stripes, and use breathing apparatus.
  • Use a preconnected hoseline of at least 1½ inches in diameter, flowing at least 125 gallons per minute (gpm).
  • Chock the wheels of the burning vehicle to keep it stationary.
  • Have a dry chemical extinguisher ready to control flammable liquid releases.
  • Avoid the vehicle’s front and rear danger zones.
  • Knock down the fire from a safe distance before approaching the vehicle.
  • Be ready for the unexpected.

BURNING VEHICLE SCENARIO

Firefighters who think that vehicle fires are just another routine run should think again. Vehicle fires can quickly escalate beyond a routine incident. Consider the following incident.

You receive a call reporting an automobile fire on a city street at dusk. A tenant on the third floor of a former factory building that has recently been converted into low-income housing makes the call. As additional calls come in, the dispatcher sends the nearest engine and ladder company to the scene.


(3) A firefighter approaches a vehicle fire involving the engine and passenger compartment at a 45° angle from the unburned side.

On arrival, the engine officer reports a heavy fire in the passenger compartment of the vehicle, which is parked parallel to the curb; no other vehicles are near it. As the engine company stretches a hoseline, one member of the ladder “takes the glass” using a six-foot hook while another walks to the front of the vehicle and prepares to force the hood open to cut the battery cable and check for extension. What is wrong with this picture so far? Water reaches the nozzle, and the nozzle team approaches the vehicle at a 45° angle from the side, directing the stream into the passenger compartment and sweeping it beneath the vehicle to cool the gas tank and undercarriage.

Before the flames fully darken down, the horn begins to sound, the headlights begin to flash, and the sound of the ignition’s cranking can be heard. Realizing that the ignition wires have shorted and the car could start, the engine officer calls for a chock. A few seconds later, the motor turns over and lurches forward as the firefighter arrives with the chock. Although he places the chock in front of the rear wheel, there is too much momentum and the flaming vehicle rolls over the chock and continues down the street. The member at the hood has been knocked down and is lying on his back, his legs under the vehicle; he is holding onto the radiator as the vehicle drags him down the street. A routine car fire has just turned into a rather hazardous incident.


(4) Hood struts are found on both sides of the vehicle. They are oriented fore and aft, to hold the hood up.

What happens next? A quick-thinking member sees a discarded TV on the sidewalk in a pile of refuse. He grabs it and throws it under the front bumper. The TV is too large (nonflat screen) for the car to drive over. It lodges in front of the front tire on the passenger side, causing the car to come to a stop. The member was not seriously hurt, but he easily could have been injured or killed.


(5) A normal and a blown hood strut. In some cases, the cylinder, when heated, can separate from the piston and become a projectile.

Lessons Learned: Expect the unexpected at auto fires. Stabilize the vehicle as soon as it can be done safely, and avoid working in close proximity to a burning vehicle, especially in front of or behind it until after all visible fire has been extinguished and all surfaces have been thoroughly cooled.

ANGLE OF HOSELINE APPROACH

Exploding bumpers along with hood, trunk, and hatchback struts are important considerations when determining the angle of approach. Though there are no guarantees, these components commonly launch in the direction in which they are mounted, which means, in effect, toward the front or rear of the vehicle. Similarly, energy-absorbing bumpers were installed in cars from the early 1970s to the late 1990s to reduce vehicle damage from low-speed impacts. They are attached to the frame of the vehicle with pistons, one on each side. If heated by a fire in the engine compartment or trunk, these pistons can fail and send the bumper in a forward direction with great force. The direction of travel will depend on how the pistons were heated. If they were heated uniformly, the bumper will travel directly forward. If one side is heated more than the other, only one piston may fail, causing the bumper to pivot like a pendulum across the front of the vehicle or careen forward at an angle.

Once ubiquitous on passenger vehicles, these bumpers are not as common at the present time, having been replaced by crushable bumpers on many late-model vehicles. However, they are still found on late model Jaguars, Volkswagens, Volvos, and many older vehicles. Because it is difficult to determine their presence when an auto is burning, it is best not to approach the vehicle directly in line with the front or rear.


(6) Firefighters widen the hose stream as they approach the vehicle to cool the passenger compartment and A, B, and C posts.

In the same way, many late model cars have replaced hood and trunk hinges with gas struts. These work fine under normal circumstances, but when heated they can burst, sending projectiles in any direction—most often toward the front or rear of the vehicle. For both of these reasons, it is wise to avoid the front of the vehicle if the engine is involved and the back of the vehicle if the trunk or hatchback is involved.

Common sense suggests that the nozzle team should assemble upwind and uphill of the vehicle as long as doing so does not place them in an unsafe traffic lane. When water arrives, they should advance toward the vehicle at a 45° angle from the corners, because this keeps the nozzle team from approaching directly inline with the front and rear and sides. Although approaching from the side is generally safer than from the ends, projectiles from side impact air bags can be expelled laterally. Obviously, if fire is confined to the engine compartment and the passenger compartment is not involved, a side approach would not be hazardous. If there is passenger compartment involvement, it is best to approach at a 45° angle and use the full length of a straight stream to darken down the vehicle and thoroughly cool the A, B, and C posts before approaching.


(7) Firefighters make an initial opening in the hood from the side of the vehicle through which they can direct a hose stream to extinguish fire and cool components beneath the hood.

Advancing the line laterally at a 45° angle not only keeps members out of the direct path of the bumpers and struts, but it also allows the nozzle team to direct the stream on two sides of the vehicle with the flick of the wrist. To add an additional margin of safety, you can approach the vehicle at a 45° angle from the unburned side (if topography and traffic allow). This means if the fire is in the trunk, approach it from a forward position at a 45° angle. If the fire is under the hood, approach it from aft. If the fire is in the passenger compartment, approach from a 45° angle from either direction. If fully involved, extinguish the passenger compartment first so that you can approach the vehicle and make access points to the interior of the hood and trunk. In any case, do not cross the front or rear of the vehicle with the hoseline if the hood or trunk is involved in fire.

NOZZLE OPERATIONS

As mentioned above, the nozzle team should stay back and use the full reach of a straight hose stream to darken down the flames before advancing. To exploit the stream’s full reach and maintain visibility, initiate the attack using a straight stream from an upwind position, especially if the wind is strong. Keep the nozzle moving and directed at all compartments of the vehicle. Periodically aim the stream down and bank it off the street to allow water to bounce up and cool the vehicle’s undercarriage and gas tank. Whenever fire is present under the vehicle, it takes priority. Extinguish it before proceeding further.

Burning rear tires and fire beneath the trunk can impinge on the gas tank, producing a stream of flaming gasoline on the roadway or a pressurized fuel vapor fire at the filler pipe. If the flexible rubber connector between the fuel tank and the filler pipe ruptures, a pressurized fuel vapor fire can forcibly exit the filler pipe. This is where the dry chemical extinguisher comes in handy. Once you have extinguished the tires and cooled the gas tank, use it to douse the fuel vapor fire. The key to extinguishing this type of fire is to cool the area around the gas tank first. Then you can use a dry chemical extinguisher directly on the vapor fire or, through an applicator, to extinguish the fire. Cooling surrounding areas with water fog before deploying the dry chemical prevents the fuel vapors from reigniting.


(8) With the vehicle stabilized and visible fire knocked down, firefighters direct the hose stream through the back seat to extinguish the remaining pockets of fire in the trunk.

For fires involving the passenger compartment it is sometimes advantageous for the nozzle crew to crouch down momentarily so they can aim the stream upward and bank it off the underside of the roof to create a sprinkler effect on the material burning below in the passenger compartment. This is preferable to spraying the stream through one window and out the other side. When the rear seats have been consumed, direct the hose stream into the trunk to extinguish any fire there.

The nozzle crew can gauge the success of the fire attack when the flames diminish and the smoke absorbs steam and turns white. When the fire darkens down, the crew can advance toward the vehicle. At this point, adjust the nozzle pattern from a straight stream to a wider angle and eventually to a medium fog pattern to provide rapid cooling to a wider area as well as broaden protection to the crew as they approach the vehicle. A fog pattern also serves to push noxious smoke away, redirect flammable liquids, and cover a broader area of the vehicle. Move the nozzle continuously to direct water over, under, around, and throughout the vehicle, giving all involved surfaces a thorough wash. As the crew advances the line, the pump operator should carefully monitor the amount of water remaining in the tank. Once the main body of fire is darkened down, the pump operator should diminish the flow and conserve water so that there is enough to complete the job.

The crew should take time to continue cooling the vehicle after visible flame has been extinguished and give the undercarriage, gas tank, passenger compartment, and bumpers a final wash down before approaching the vehicle closely. The nozzle crew should also direct the stream onto smoldering tires, which can be subject to rekindle because of the heat-retention qualities of the steel belts, which can prompt reignition.

OVERHAUL

Complete extinguishment requires that the hood and trunk be opened, and a close approach to the vehicle is necessary to conduct forcible entry. Attempt these operations only after the fire is darkened down and all areas are washed and cooled, after which you should approach the vehicle from the side, not from the ends. To avoid the bumper, you can make an initial hood opening at the side of the vehicle near the wheel well. Working from the side, it is possible to drive the halligan into the hood and create an opening through which to direct a stream of water beneath the hood. When the hood is pried up, flames may flare up, so it is important to keep the nozzle ready. When the fire has been extinguished within the confined space beneath the hood, steam generation has been diminished, and the bumpers have been thoroughly cooled, crew members can initiate efforts to open the hood from the front of the vehicle so that it can be opened fully, smoldering debris can be completely extinguished, and the negative battery cable can be cut.

In the case of hidden fire in the trunk, it is possible to puncture a hole through the speakers in the rear deck below the back window or follow a similar procedure as used for the hood. Overhauling the trunk also includes completely extinguishing the spare tire and giving it a thorough search for any human remains. Some departments are finding a new use for the old Navy nozzle applicator pipe in extinguishing stubborn, smoldering fires in tires, wheel wells, or beneath the car where a normal nozzle stream does not reach. Both water and dry chemical can be directed through the pipe.

•••

Vehicle fires can be unpredictable. Gas-filled struts, aerosol cans in the trunk, plastic composite gas tanks, and new fuel-efficiency technologies can lead to unexpected developments at an otherwise routine incident. Although it is impossible to predict what will happen, taking a cautious approach to vehicle fires can limit the hazard.

References

NFPA’s U.S. Vehicle Fire Trends and Patterns, Marty Ahrens, July 2008: http://www.nfpa.org/assets/files//PDF/Research/VehicleFires08.pdf/.

NFPA’s Fire Loss in the United States 2007, Michael J. Karter Jr.: http://www.nfpa.org/assets/files/PDF/OS.fireloss.pdf/.

USFA’s Fire-Related Firefighter Injuries in 2004report: http://www.usfa.dhs.gov/statistics/reports/2004injuries.shtm/.

USFA Highway Vehicle Topical Report October 9, 2008: http://www.usfa.hs.gov/media/press/2008releases/100908.shtm/.

FireLink.com Is it Time to Change Our Training Yet? Lee Junkins: http://www.firelink.com/training/articles/332-is-it-time-to-change-our- training-yet-/.

DOUG LEIHBACHER, a 28-year veteran of the fire service, retired as an assistant chief from the Yonkers (NY) Fire Department, where he served as chief of training. He has an associate degree in fire protection technology and a bachelor’s degree in education. He is certified in incident command, incident safety, code enforcement, and hazardous materials and is a certified fire instructor and municipal training officer. He has contributed articles to Fire Engineering since 1994.

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