Vehicle Fires: Is It Time to Change Our Training?

BY LEE JUNKINS

Auto manufacturers have spent billions of dollars making today’s vehicles safe. With air bag systems, occupant classification systems, cushioned bumpers, crumple zones, and high-strength steel reinforcement, vehicles are literally built to wreck. But, today, there is not one vehicle built to burn.

Today’s vehicle fires have proven to be some of the most dangerous calls we can make. A 2008 National Fire Protection Association report showed that nationwide one out of every four fires to which we respond is a vehicle fire and that the lowest number of vehicle accidents occurred in 2007, when 278,000 car fires were reported.

Because we have not changed our vehicle fire training to adapt to strategies needed for the potential hazards of the new technologies in today’s cars, we are teaching firefighters that they are supposed to be in the paths of the dangers these new vehicles pose when fighting a vehicle fire.

After personally experiencing two of these dangers on one vehicle, I began a study of all the dangers that the new technologies of today’s vehicles present for us when they are involved in fire. These findings are discussed below.

Among the primary dangers firefighters face when fighting fires in today’s vehicles are the following: bumper struts and compressed-gas lifting struts, which shoot out from under hoods and hatchbacks like arrows, severely injuring firefighters; air bag inflators, which blow out through the roofs and explode into shrapnel; plastic fuel tanks, which melt and dump gallons of hot gasoline at the firefighters’ feet; molten magnesium, which splatters out from under hoods and dashes; and alcohol-based fuels, which cannot be extinguished with normal agents.

 

BUMPER STRUT

 

In 1973, the fire service developed an approach to a burning car that would protect firefighters from the dangers of a bumper strut explosion. This approach is still being taught nationwide, even in our largest academies. Ironically, however, according to the Insurance Institute for Highway Safety, 95 percent of today’s vehicles are not equipped with bumper struts.

 

Present Training

 

We teach our firefighters as follows:

  • Wash out any spillage under the car from a long (safe) distance with a straight stream, deflecting the water off the ground upward to cool the gas tank, and then quickly knock down the fire.
  • Approach the vehicle diagonally or at a 45° angle to one corner of the car, and cool the tire and bumper with a broken stream.
  • Reach through the window or open the door and put out the fire in a circular motion.

 

The original objective of this approach was to protect the firefighter from an exploding bumper.

Scenario:On March 29, 2005, the Salinas (CA) Rural Fire District responded to a vehicle fire. Three firefighters approached the vehicle at a 45° angle from the driver’s side of the front bumper, just as they were taught. Just before they applied water to the fire, there was a loud explosion. The three firefighters assumed that a tire had exploded; they continued the extinguishment. After they knocked down the fire, an officer found the complete bumper and left strut lying several feet from the vehicle. The left strut had exploded, launching the bumper about 25 feet from the vehicle; it penetrated a wooden fence (photo 1). The bumper, weighing at least 50 pounds, traveled fast enough so that the three firefighters did not notice it even though they were standing within 10 feet of it at the time. The bumper had detached from the passenger side of the vehicle at a 45° angle, the same angle at which firefighters are taught to approach the vehicle.

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(1) Photos by author unless otherwise noted; photo 1 by Chief Michael Urquides, Salinas (CA) Rural Fire District.

Did you notice the obvious concerning photo 1? If the passenger side strut had failed first, or if the firefighters had chosen to approach from the passenger side, three firefighters would have been seriously injured.

The reality is that both struts must receive the exact same amount of heat for the exact same time for both to explode at the same time, which is the only way that a bumper can be launched straight forward. The odds of that happening are zero.

When one strut explodes, the bumper is going to lead off in one direction or the other every time. The only variance depends on the amount of resistance the opposite side provides. In the Salinas fire, the left strut exploded, throwing the bumper around to the right, but the force was great enough to rip the bolts out of the right side (photo 2), launching the complete bumper away from the car at a 45° angle, the angle at which our firefighters are trained to approach a burning vehicle. At other times, one side will be strong enough to hold the bumper, and the strut itself will exit the vehicle as a projectile (photo 3).

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(2) Photo by Chief Michael Urquides, Salinas (CA) Rural Fire District.
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(3) Photo by Gary Thornhill; courtesy of Thornhill Photography.

 

ELECTRICAL SHORT-CIRCUITING

 

The Edgely (PA) Fire Company responded to a reported vehicle fire. On arrival, firefighters found light smoke coming from under the vehicle’s dash. With no flames showing, their natural response was to find and eliminate the source of the fire. As they began to investigate the dash, two loud explosions occurred approximately one to two seconds apart. The driver air bag unexpectedly deployed, striking one firefighter in the side of the head, knocking him unconscious. At the same time, the passenger air bag deployed, striking the second firefighter. Both were hospitalized with their injuries.1

Electrical shorting is one of the major causes of vehicle fires. If the fire is caught in time, it usually tends to be a minor fire, but do not be deceived: When the air bag wires short-circuit, the air bags may deploy.

 

PYROTECHNIC GAS GENERAT0RS/INFLATORS

 

In the late 1970s and early 1980s, manufacturers began installing driver air bags in their new cars. These air bags contain pyrotechnic gas generators, or inflators, that use sodium azide or its equivalent as their propellant. Sodium azide is the same solid fuel used to send rockets into space. At 350°F, it becomes a rapidly burning fuel that produces huge amounts of nitrogen gas to fill the air bag.

Operations involving these systems are not like extrication procedures where we could cut the battery cables and shut down the system. This type of air bag will deploy when it is exposed to the heat of a vehicle fire. There is no way to shut them down or stop them. When the sodium azide experiences temperatures above 350°F, it will ignite, starting a very explosive chemical reaction that will normally deploy the air bag and allow the nylon bag to melt in the flashover-type fire conditions.

In June 2005, I was the officer at a fully involved fire engulfing a 2004 Ford Ranger and a large tree that was hanging over the house. After the fire was extinguished, I thought I would give two rookie firefighters experience and assigned them to overhaul. They donned and checked each other’s gear. During all of this time (approximately five to eight minutes), no flames were showing. As the firefighters opened the driver’s door, two loud explosions occurred. Both the driver and passenger air bags deployed about 15 seconds apart, throwing debris in all directions, narrowly missing the firefighters. During the investigation, large pieces of the nylon air bag were found 47 feet behind the vehicle (photo 4).

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Since this was the overhaul stage and no flames had been showing for several minutes, I set out to find the source of heat that ignited these inflators. We found that it was basically heat transfer. Since overhaul was not yet performed, it was possible that enough heat still existed under the dash to allow the passenger air bag to be exposed. However, looking at the driver air bag, the steering wheel is a very small, wide-open area that has no surrounding material to smolder or retain heat.

In analyzing this situation, we found two things:

1 These early inflator housings were made of aluminum. As aluminum is heated, the heat tends to equalize throughout the structure by means of conduction. Because aluminum is a very poor conductor of heat, this heat transfer is a very slow process. Therefore, aluminum retains heat for long periods of time and is very slow to cool without the help of a cooling agent. Since the inflator was totally covered, our water stream could not directly reach it. The heated housing may have taken several minutes to transfer the heat to the sodium azide inside the housing, thus delaying deployment. Although this situation has proven to be true, our second situation seems to answer more questions about the experience.

2 If the air bag cover and nylon bag had already been melted, the nitrogen produced by the explosion would have been blown out into the atmosphere as a blast of air. There would not have been any fragments of debris.

In studying the construction of the air bag, we find that the bag itself is made of Nylon 6,6 High-Tenacity air bag yarn, which, according to DuPont Chemical Corp., the leading manufacturer of this fiber, has a melting point of 505.4°F. With the bag folded inside its cover, it would act as insulation, preventing the flames from entering the inflator through the filter screen but, at the same time, storing the heat within the folds. With the nylon having a 505.4°F melting point, it can very easily store 350°F, slowly transferring it through the filter and eventually igniting the sodium azide, which would explain the deployment’s occurring in the overhaul stages.

Although not yet melted, the nylon bag’s being exposed to these kinds of temperatures would bring it to its melting point, allowing it to shred when exposed to the tremendous pressure of the nitrogen blast, explaining the fragments of nylon that were thrown in all directions. As you can see, even a normal deployment can be both delayed and extremely dangerous.

 

Inflator Ejection

 

In more extreme cases, the inflator housing itself will eject, many times penetrating the roof of the vehicle and/or exploding into shrapnel.

On December 27, 1997, Denver (CO) fire marshals investigated a vehicle fire involving a 1996 Ford Aspire in which the air bag did not deploy in the normal manner. During the investigation, they found a four-inch hole in the roof of the vehicle, just above the steering wheel, where a projectile had penetrated the metal body of the car (photo 5).

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Further investigation showed that the driver frontal air bag inflator was missing and large pieces of metal shrapnel were found 100 feet behind the vehicle.

On June 11, 2008, a police officer arrived on the scene of a fully involved 1995 BMW. On arrival, the officer reported witnessing the driver frontal air bag and inflator deploy, blowing straight through the windshield and approximately 40 feet into the air, landing in the roadway.

The question here was how these inflator housings came loose from the steering wheel. They are bolted to the center of the steering wheel with four bolts designed to withstand the pressure of the air bag deployment. Again, we found two different situations.

First, many inflator housings are made of aluminum and have thin mounting flanges extending from the sides (photo 6). The flanges are then bolted to the steering wheel’s center hub. The canister is a much thicker metal and sits in an indentation in the center hub, somewhat protecting it from the heat. The front half of the housing (the filter screen) is covered by the nylon bag, giving it some insulation. Therefore, the thin aluminum flanges are the most exposed part of the inflator. As they heat, the aluminum softens and allows the thin flanges to fail under the extreme pressure of the sodium azide explosion. Second, most of the later inflators have a steel housing mounted much the same way as the aluminum one (photo 7).

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In looking over many burnt vehicles, I found that in the cases where most of the steering wheels were missing, the inflators were burnt severely enough so that the aluminum steering wheel hub melted and the shell of the inflator was lying in the floorboard, indicating that it had experienced a normal deployment earlier in the fire and then was released as the center hub melted.

On one vehicle, the inflator was still in place, but two of the mounting bolts were missing and the threads were stripped inside the bolt holes of the center hub. On five vehicles, the inflator was still mounted, but it was very loose, which leads me to believe that the aluminum center hub of the steering wheel must get hot enough to expand and weaken the grip of the threads around the bolts, allowing them to strip out under the pressure of the sodium azide explosion. If this weakening is severe enough, it would allow the inflator housing to eject through the roof, as we have seen in the Denver incident above.

Warning!Never put any part of your body inside the vehicle.

 

Compressed-Gas Inflators

 

In the late 1980s and early 1990s, manufacturers began using compressed-gas inflators instead of the pyrotechnic type in their passenger and side impact air bags. They are storage containers that hold 3,000 to 4,500 pounds per square inch (psi) of compressed argon gas. There are many sizes and shapes for different applications. Like the nitrogen in the bumper struts, argon is nonflammable and nonexplosive, but it has a very high rate of expansion when exposed to very little heat. Most of these inflators, when heated, will deploy the air bag normally, and the bag will melt away.

Although rare, as with the pyrotechnic type, these compressed-gas inflators have been reported to explode, throwing shrapnel in all directions. These cylinders have no built-in pressure-relief features. These storage containers have a bladder, much like a soda bottle cap, that is supposed to melt and allow the gas to escape into the nylon bag.

How often can we expect a catastrophic explosion from one of these inflators? Capt. Gary Rhodes of the Ft. Worth (TX) Bomb Squad and I timed many of these canisters to see how much heat they could stand and how long it would be before they deployed or exploded. For our source of heat, we used traffic flares, which we lit with electric matches. We timed them with a stopwatch. The results are below.

 

Passenger Air Bag Inflator

 

With two flares placed on each side of the canister, the average time from the ignition of the flares to the deployment of the inflator was 20 to 22 seconds (photo 8). To reduce the amount of heat, we resorted to one flare on each side. The average time of deployment did not change, confirming argon’s low tolerance to heat. In each of these cases, the inflator released its gas normally; there were no catastrophic failures.

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Side-Impact Air Bag Inflators

 

We then exposed the small compressed gas inflators from the side-impact air bags to the heat of one flare; the average time of deployment was 13 seconds. Most released their gas as a normal deployment, but one was violently propelled across the field. On inspection of that inflator, we found that the small gas cylinder had separated from the remainder of the assembly instead of deploying normally.

In two later tests, thanks to two air bag recalls, we were able to gather many identical hybrid compressed-gas inflators and expose them to the same heat. The passenger air bag inflators were eight inches long and 2¼ inches in diameter and contained 4,000 psi of argon gas.

In totaling the results of these two tests, we found that when exposed to the heat of one flare on each side and placed in the middle of the canister and two inches away from it, the following occurred:

  • Ninety-two out of 100 released their gas as a normal deployment within the 20-second time range seen in the first test.
  • Six violently ruptured the side of the canister, which, given the benefit of the doubt, could possibly have been a result of the heat being concentrated to the one area of the metal cylinder, but proves that they are capable of rupturing rather than melting the bladder and deploying as normal.
  • Two blew out small bits of shrapnel, which were determined to be the metal screen around the electronic igniter squib.

 

We then exposed 20 Audi compressed-gas inflators from the door-mounted side-impact air bags to the heat of one flare:

  • One exploded into three pieces.
  • Two ruptured on the side next to the flare.
  • Seventeen released their gas as in a normal deployment.

 

Although these were not scientific tests, note that just applying a small amount of heat caused every one of the inflators to have some type of reaction to the heat, and they reacted within seconds of being exposed.

As you can see, in a vehicle fire with temperatures reaching the 1,000°F range, we would have no time to think about it. When the heat reaches the canister, the air bag is going to deploy in some manner.

Members of the McKinney (TX) Fire Department responded to a fully involved 2002 Dodge. After extinguishing the fire, they found the passenger air-bag housing and hybrid compressed-gas inflator approximately 120 feet in front of the vehicle. The firefighters did not know that this explosion had occurred before the fire department arrived, again confirming the immediate reaction of these inflators when exposed to heat.

Notice the thickness of the metal edges in photo 9. They are made of very heavy metal. We can only imagine the tremendous pressure that it takes to rupture this cylinder, rip it out of its mountings, penetrate the metal body of the vehicle, and then propel it 120 feet.

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(9) Photo courtesy of Ron Moore.

In examining these ruptured cylinders, we find that when the bladder fails to melt, the cylinder displays all of the same markings and indications as a propane cylinder does after experiencing a boiling-liquid, expanding-vapor explosion (BLEVE).

In Flagler County, Florida, while investigating a burned-out 2001 Nissan Altima, fire marshals found a hole in the roof of the vehicle where a projectile had exited. The hole was found to be in perfect alignment with the missing argon cylinder from the passenger seat-mounted side air-bag inflator.

This separation of the inflator housing and the gas cylinder is the exact same separation we saw in the inflator that flew across the field in our first test. When ejected, the cylinder acts as a 1- × 1½-inch bullet (photo 10).

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(10) Photo by Alex Stevenson, Flagler County (FL) fire marshal.

 

COMPRESSED GAS-LIFTING STRUTS

 

It is common to see hood struts exploding and shooting out like arrows in today’s vehicle fires. Drew Hill of the Windsor Locks (CT) Fire Department was one of the first of many injured by these exploding cylinders (photo 11). Today, they are no longer just hood struts; they are used also on trunk lids, hatchback doors and windows, third-row seats in SUVs, camper shells, and even fire apparatus compartment doors. Some SUVs have four on the hatchback alone.

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(11) Photo courtesy of the Windsor Locks (CT) Fire Department.

Not only are these explosions common, but they are very violent. Firefighters in Aberdeen, Washington, safely watched from behind a building as the right strut on the rear door of a 1989 Dodge Caravan exploded. The cylinder end was found 44 feet down the parking lot with one end split open, much like a cylinder that had been involved in a BLEVE. The edge of the hatchback door was made of three layers of metal, shaped to form a two-inch tube. The explosion bent this reinforced door outward eight inches as the strut exited at a 45° angle from the vehicle.

In Montreal, Canada, in September 1999, firefighters responded to an incident involving a 1997 Pontiac transport van. While donning his face piece, a firefighter said he heard a loud explosion and felt something hit him in the neck. He was transported to the hospital; X-rays showed the cylinder end of a compressed-gas strut was protruding out of his neck. It missed his jugular vein by 2mm (1⁄8 inch). The strut on the van’s rear door had exploded and was propelled through the van’s side wall; it had traveled approximately 35 feet and penetrated the firefighter’s neck.

Firefighter Chris Marsh, Sacramento Metro (CA) Fire Department, explains his experience with a gas strut that exploded under the hood:

I moved to the passenger side of the vehicle and started to extinguish the fire through the front grille when, all of a sudden, we heard a large explosion. The cylinder end of the strut shot out through the engine compartment and grille and pierced my bunker gear and upper leg. The strut was so hot that it actually cauterized my wound as it passed through. It just missed my femur. It exited through the back of my leg and was found 50 feet down the road.

 

In researching the many case histories sent to me, I have found two things that seem to be common to all struts, whether front- or rear-mounted: They all seem to exit the vehicle straight out or at a 45° angle from their original mounting position.

Again, our training teaches us to approach the vehicle at a 45° angle to the burning end of the vehicle. In reality, we are teaching firefighters that they should be standing in the path of one of these potentially exploding struts.

Let’s look a little closer. If the fire is in the engine compartment, we have always been taught to knock down the fire and usually forcibly open the hood to get to the base of the fire. To do this, we have to put a firefighter directly in front of the bumper (which could be ready to explode) and center him between both of these compressed-gas struts we know are in the midst of the main body of the fire, which was the position of Hill and Marsh when they were injured.

I ask again, Is it time to change our training?

 

PLASTIC OR COMPOSITE FUEL TANKS

 

Many of today’s vehicles use some type of plastic fuel tank and pressurized plastic fuel lines. These tanks melt very quickly in a fully involved car fire, dumping their hot load right at the firefighter’s feet. The fuel lines also hold a constant pressure of 15 to 95 psi at all times, even when shut off for many days. When melted, they spray their fuel under the vehicle, quickly spreading the fire.

In Missouri City, Texas, four firefighters entered a garage from a side door to battle a vehicle fire inside. Within seconds, the plastic gas tank dumped its fuel on the floor, engulfing all of them in flames.

During the interview, the chief showed me his helmet and face piece. The damage occurred in about five to 10 seconds. The respirator itself fell off. Luckily, they were able to escape.

Photo 12 shows the fuel tank from the same 2004 Ford Ranger discussed in the air bag section above, which dumped about 10 gallons of gas on the ground, creating a circle of fire about 25 feet in diameter. Two manufacturers supply us with special suppression agents for demonstrations in our classes. Both of these products are extremely good; however, we used one of them on this tank, but it still flared up seven times. In investigating, we found that because of the tank’s shape and location, some pockets of fuel could not be reached with the extinguishing agent and, therefore, were not affected by it. Be aware that this situation is going to exist with every melting tank.

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As plastic begins to melt, it sags and forms pockets. Each of these pockets will hold a certain amount of fuel until it melts through. Since the tank is mounted under the vehicle and inside the framework, it is impossible to reach every part of it with any type of extinguishing agent.

On August 8, 1999, three volunteer firefighters were burned, one critically, while trying to control a recreational vehicle (RV) fire alongside a single-family dwelling. This victim died eight days later as a result of third-degree burns over 96 percent of his body.2

Two volunteer fire departments responded to this incident: Volunteer Fire Department #1 (VFD #1) with Engine 1, staffed by a driver/operator; and Volunteer Fire Department #2 (VFD #2) with Engine 2, staffed by a driver/operator and one firefighter (the fatality), who rode as the passenger in the cab of Engine 2. Another firefighter from VFD #2 responded in a privately owned vehicle. Engine 1 arrived and was positioned in the dwelling’s driveway. The driver/operator used the booster line to protect the exposed side of the dwelling and then tried to control the RV fire. Engine 2 arrived less than five minutes later and also took a position in the driveway.

While firefighters from Engine 2 attempted to place in service the preconnected 1½-inch attack line from the rear hosebed of the apparatus, the RV’s gasoline tank ruptured, releasing about 50 gallons of gasoline. The gasoline ignited, and the burning fuel spilled down the inclined driveway. All three members of VFD #2 suffered thermal injuries.

 

MAGNESIUM COMPONENTS

 

Today manufacturers have been forced to cut every ounce of weight possible to lower costs. One way of doing that is to use magnesium extensively. Magnesium is stronger and one-third lighter than aluminum and can be molded and machined into almost any shape. Manufacturers are using it for almost all the brackets under the dash, transmission housings, wheels, and suspension parts; in some cars, it is used for as much as 45 percent of the exterior engine parts.

We know that magnesium will burn and that, once burning, it is extremely hard to extinguish, but do we really understand the dangers of fighting a magnesium fire? Photo 13 shows the violent reaction magnesium had to water in a car fire in Delray Beach, Florida. The reaction occurred from just a very small bracket on the steering column. The sparks seen in the photo are much hotter than our bunker gear is designed to withstand, and they will penetrate it.

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(13) Photo courtesy of Delray Beach (FL) Fire Department.

With so much magnesium being used today, our normal procedure of opening the hood and applying water is sure to put firefighters in serious danger.

 

DRIVESHAFT EXPLOSIONS

 

Like the compressed-gas cylinders, driveshafts can produce very violent explosions that give off large amounts of shrapnel. Comstock (MI) Fire & Rescue responded to a fully involved van fire. During the extinguishment, a very violent explosion occurred. The driveshaft exploded, ripping through the floorboard and producing many pieces of shrapnel.

 

ALTERNATIVE FUELS

 

In fighting the gas and oil crises of today, many new fuels have been developed, among them ethanol. The E-10 or 10 percent version of ethanol added to all gasoline today does not seem to pose too much of a problem; but, as manufacturers began to develop flex fuel vehicles, we have begun to see more and more E-85 ethanol stations. This fuel is cheaper than gasoline; soon, people will be putting it in their nonflex fuel vehicles. According to the Association of Oil Pipelines, ethanol is very corrosive and will cause the early metal gas tanks and fuel lines to leak, causing more car fires. This, in turn, will pose many problems for firefighters, because the normal extinguishing agents we use will not extinguish an alcohol fire. Although some foams will seem to put out the fire, if the foam blanket is interrupted, the fire will reignite. These fires can be extinguished only with very expensive alcohol-resistant foams that most departments do not carry on their apparatus.

Considering all of these dangers and the many other dangers we face in fighting today’s vehicle fires, I ask again, Is it time to change our training?

 

ASSESSING OUR CURRENT TRAINING

 

Our present, nationally accepted, vehicle fire training teaches us to reach through the window or normally open the door and put out the fire in a circular motion. With the door open on either side, let’s look at what we are teaching, compared with the potential dangers presented by today’s safety restraint systems.

  • Directly in front of the firefighter’s face would be a driver or passenger dual-stage air bag. Both are known to explode into shrapnel and penetrate the metal body of the vehicle.
  • An overheated compressed-gas inflator mounted in the A post or A pillar area could be to one side of the firefighter.
  • To the other side of the firefighter could be a deploying seat-mounted air bag or a compressed-gas inflator exploding like a large bullet.
  • A deploying curtain air bag or an exploding compressed-gas inflator could be over the firefighters’ heads.
  • In front of firefighters’ legs could be a deploying knee air bag or an exploding pyrotechnic or compressed-gas type inflator.
  • An exploding pyrotechnic seat-belt tensioner could be beside firefighters’ legs.
  • Behind firefighters could be a deploying door-mounted air bag or an exploding compressed-gas inflator.

 

What’s even worse is that these hazards are also found in the C and D posts, anywhere along the roof rails, and in the rear seat- or rear door-mounted air bags. And even more dangerous is that our training tells firefighters that they should be positioned in this dangerous area to properly fight a vehicle fire.

Following are some of the approaches to vehicle incidents with which I have experimented and which I believe may make an aggressive operation much safer when facing the newer technology vehicles. These examples are meant as a foundation on which to build a safer training program.

With so many makes and models of vehicles being equipped with dozens of different systems that affect our safety, and since these systems are constantly changing, it is impossible for a firefighter to remember the dangers involved in each model. To develop a safe general approach, we must assume that every vehicle is equipped with every one of these systems. Also, we must place vehicle fires into one of the following four categories.

  • Front-end fires: bumper to inter-dashboard.
  • Rear-end fires: rear seat to rear bumper.
  • Passenger compartment fires: dash to rear seat.
  • Fully involved fires: bumper to bumper, or a combination of any two of the other categories.

 

By categorizing the fire in our size-up, we can initiate a safer, faster attack. Using the approaches in this article, we can to date mark 33 danger zones on one vehicle and never put a firefighter in harm’s way. None of us can remember all 33 of these dangers. However, by categorizing the fire, we can remember the six or seven dangers associated with that particular area of the vehicle.

 

COMPARTMENTALIZING PRINCIPLES: A SAFER APPROACH

 

 

Approaching a Rear-End Fire

 

The danger zones for this type of fire include the following: the plastic fuel tank, rear bumper, compressed-gas cylinders in C or D posts, rear tires, trunk lid with compressed-gas struts, and trunk contents.

Current training: Wash out under the car with a straight stream, deflecting water up to cool the tank. Approach the vehicle at a 45° angle to one corner of the bumper. When knockdown is accomplished, cool the bumper struts, making it safer to work on getting the trunk lid open. This takes time, but remember that the bumper can blow off. You must cool it before you can attempt to open the trunk, which may present a hassle. At the same time, the seat of the fire is getting hotter, and you are directly in front of two hot gas struts on the trunk lid.

The fire’s main fuel is the foam rubber in the back of the seat and the thin cardboard shelf in the rear dash, which allows the fire to spread quickly to the compartment area and the compressed-gas inflators in the C or D posts. With this spread of fire, you now have a fully involved fire, and you are about to open the trunk to a flash of fire and the unknown hazards of its contents.

Revised approach: I am experimenting with approaching diagonally from the front of the fire area instead of the corner of the car (photo 14). Just as before, from a safe distance, wash out under the car while cooling the tank. Although this is doing the same job, you are at the same time accomplishing two other objectives: (1) protecting the crew from a flying bumper and the trunk lid struts; and (2) pushing the heat away from the unburned area, slowing the spread of fire into the compartment, where many of the dangers are located.

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By approaching the car at this angle, you can safely break the rear door glass and cool the C/D posts and air bags, avoiding their potential failure (photo 15).

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Remember the rule: Never have any part of your body enter the vehicle until every vehicle part has been cooled. Using a pike pole, tear out the rear dash, exposing the speaker hole into the trunk, without entering the vehicle (photo 16).

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By putting water through this hole, you cool the base of the fire in approximately the first minute of the attack, as compared with the time it takes to cool the bumper struts and open the trunk. At the same time, the steam conversion forms a blanketing effect, smothering the fire. You are actually using two parts of the tetrahedron: taking away the heat and smothering the oxygen.

While the steam blankets the fire, cool the tire, bend the edge of the trunk lid with a halligan bar, and cool the strut. Reach around the corner and cool the bumper strut on that side of the car. Never cross in front of the burning end; go around the nonburning end of the car to the other side and cool the tire, trunk lid strut, and bumper strut on that side. Open the trunk safely, and overhaul.

Each time we used this method, we found the flames to be completely out when opening the trunk. Steam conversion worked every time. Although it is the best method we have tried, we later found one problem with it: Some after-market speakers are bolted in and are difficult to remove, whereas factory-installed speakers are easy to knock out.

Thinking of the opening behind the seat, we tried to hook the center of the seat back and pull it out, which was not successful. We then hooked the seat back about six inches from the corner, and it came loose with one small pull. Using this opening, we followed the same procedures as before; each time we opened the trunk, we found a very good knockdown but still some small amount of flames. We tried pushing the seat back into position and stopping the steam from escaping. We opened the trunk, and there was no fire. The smaller hole retains our steam, putting out the fire. This method is easier than using the speaker hole, but it allows a greater amount of heat to enter the compartment when it is first opened. Pushing the seat back into position is a must.

 

Approaching a Front-End Fire

 

Danger zones include the following: bumper, hood struts, tires, air bags in the dash, inflators mounted in the A posts, and magnesium engine parts.

Current training: As with the rear-end fire, we have always washed under the car from a safe distance and made a quick knockdown. We approach the fire diagonally to the corner of the bumper and cool the tire and bumper struts with a broken stream, again putting the firefighters in danger of another bumper explosion incident. We then forcibly open the hood to the seat of the fire, once again putting the firefighters in danger of another Hill or Marsh incident. During all of this time, the seat of the fire is getting hotter, and the fire is spreading to the unburned area of the car—the dash, where two compressed-gas inflators may be mounted in the A post and a passenger air bag; two knee air bags; and a driver air bag are located. We do not know if they will deploy or eject the inflators. Once the hood is opened, water is applied to the engine, which could contain as much as 45-percent magnesium, and there are other dangers such as an air-conditioning system that may explode or pressurized fuel lines that could spray fuel at the firefighters. This may sound extreme, but, as we have seen above, every one of these conditions is a true possibility and has been backed by a documented case history.

Revised approach: Using a 1¾-inch line, wash under the vehicle from a safe distance (deflecting water up into the engine compartment area), and quickly knock down the fire.

Approach the vehicle at a 45° angle from the rear of the fire area (photo 17), again pushing the heat away from the unburned area. Cool the door area and the A post, making sure that they are safe to approach. With a broken stream, cool the tire. Break the door glass and cool the A posts and dash, preventing the spread of fire and any air bag failure. Cool the hood; direct a stream under the rear edge to cool the compressed-gas strut.

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(17)

Using a halligan bar, slide the adz end into the edge of the hood and pull up on the bar, creating about a two-inch opening (photo 18). This allows you to shoot a good stream of water on the base of the fire, creating steam conversion within the first two minutes of the attack. It also eliminates any chance of the magnesium’s splattering back on the firefighters and allows you direct access to the hood strut. Be sure to push the hood back down to keep the steam from escaping. Again, the steam will begin to smother the fire as you work. Reach around the corner and cool the bumper strut on that side. Go around the nonburning end of the car and repeat the same on the other side.

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(18)

Never open the hood excessively; this allows much of the steam to escape and puts the firefighters in danger of a magnesium splatter.

Photo 19 was taken after we had tried three burns using this approach. By first cooling the dash, you may save the hood latch cable, shortening the time you must work in the front danger zone. You can then overhaul from a side position.

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(19)

In photo 20, steam conversion nearly put out the fire. In the overhaul stage, we now could see and avoid any remaining magnesium fire.

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(20)

 

Approaching a Compartment Fire

 

The danger zones include the following: inflators in the A posts, the driver air bag, the passenger air bag, two knee air bags, two to four door-mounted air bags, two to four seat-mounted air bags, two to five curtain air bags with inflators mounted anywhere along the roof rail, seat-belt tensioners, and magnesium brackets.

Current training: Approach the vehicle doing a quick knockdown; reach through the window; or, as many are taught, open the door and put out the fire in a circular motion. For safety, as already pointed out, assume that every vehicle is equipped with all of today’s systems. With the door open on either side, we see that the firefighter would be standing in the direct path of nine to 10 documented dangers.

New approach: Although the fire is confined to the inside of the vehicle, we must still do a washout under the car; radiant heat could melt a plastic fuel line mounted under the floorboard.

With a window down, quickly knock down the fire from a safe distance; however, with today’s air-conditioning and heating systems, the windows will normally be closed. In this case, approach the vehicle to access the fire. If at all possible, approach from the front of the driver’s side, which is safer because the steering wheel is angling to the rear should the driver air-bag inflator eject. As we have seen in the McKinney incident above, the passenger air bag ejected to the front of the vehicle. Also, the A post is a much smaller area to retain heat around the inflator than the C post, and the C post is known to contain many more inflators than are mounted in the A post on today’s cars.

With this in mind, we approach the vehicle while cooling the A post and driver’s door, break the door glass, and retreat to a safe distance and thoroughly knock down the fire. With the small opening of one window, we again create steam, helping to knock down the fire.

Once the fire is knocked down, approach the window at a 45° angle. Starting with the passenger rear corner, thoroughly cool everything that can be reached without stepping in front of the door.

Go around the car, approach at a 45° angle, and break the rear window on the passenger side. Starting with the driver’s front corner, cool everything that can be reached from this position. With the area in which you are now standing having been thoroughly cooled and the passenger front window protecting you from flying air bag debris, you can safely step forward and cool the left rear corner. Go back around to the driver’s side and cool the passenger’s front corner.

 

Approaching a Fully Involved Fire

 

Danger zones: The average 2003 and later models have at least 22 danger zones; some have as many as 47. In studying every angle of attack, we believe the only safe way is to start with a fully defensive attack.

In a fully involved fire, the windows will always vent themselves, allowing you to make a good knockdown from a safe distance. Once the fire is completely knocked down, approach the vehicle at a 90° angle and in the direct center of the B post to start overhaul procedures. This will keep you out of the path of all exploding struts. Cool the exterior of the doors and posts where inflators may be mounted. Thoroughly cool the complete interior of the compartment area from this position. Once cooled, from this position begin the same approach as for a front-end fire and the same approach as for a rear-end fire to accomplish a full overhaul.

Over the past four years, I have thoroughly studied each of these dangers and the locations of their components to develop a new and safer approach to a burning vehicle. In doing so, I have seen many patterns develop requiring a standard set of rules for vehicle firefighting. First and foremost is what I call the “Golden Rule of Vehicle Firefighting”: If you see flames on arrival, that vehicle is already a total loss. Whether the car is worth $100 or $175,000, do not risk your life to save a junk car.

 

LESSONS LEARNED AND REINFORCED

 

 

  • Never approach a burning vehicle without full bunker gear and self-contained breathing apparatus. The plastics and materials that make up today’s cars give off hundreds of deadly poisonous gases. Many plastics, when burned, emit a group of deadly poisons named dioxins. These toxic chemicals contain chlorine and are produced when chlorine and hydrocarbons are heated to high temperatures. Inhaling dioxins or being exposed to their fumes can have deadly results.
  • Never cross in front of the burning end of a vehicle. Always go around the nonburning end of the vehicle.
  • Never place any part of your body in the vehicle until every part of that car has been completely cooled. Remember the air bags deploying in the overhaul stage and inflators blowing out through the roofs and the gas cylinders throwing shrapnel in all directions. They are hand grenades with the pin already pulled.
  • Never open the hood, trunk lid, or hatchback without first bending the edges and cooling the struts. Most of them are mounted on nylon sockets that are probably melted, and the heated cylinders have built up pressure inside them.
  • Always use at least a 1¾-inch hoseline and an adjustable fog nozzle to attack a vehicle fire. For years, some of us have used a one-inch hoseline or a red line to attack vehicle fires.
  • We need a lot of water, real fast, and from a long distance for the new technology we are facing. With plastic gas tanks, plastic fuel lines, and dozens of gas cylinders that could explode, we need a fast knockdown of the fire from a long distance before approaching the vehicle and a fog stream to protect our crew while approaching the vehicle in case one of these gas tanks were to fail.
  • Always place the apparatus uphill from the burning vehicle. This has always been a part of our training, but today this is no longer an option—it is a must. With the new plastic gas tanks and pressurized plastic gas lines running all the way to the front of the car, we are going to have gas running down the hill.
  • Always have a member stand by with a 20-pound dry chemical extinguisher should a fuel tank rupture and firefighters be caught in the spill fire.

 

 

Endnotes

 

1. Sommers, Dave, All world auto.com, April 24, 2003.

2. National Institute for Occupational Safety and Health Firefighter Line-of-Duty Death Report #99-F34, “Recreational Vehicle Fire Claims the Life of One Fire Fighter and Injures Two Other Fire Fighters-Arkansas,” March 8, 2000.

LEE JUNKINS is the chief and founder of Midsouth Rescue Technologies and the founder and head presenter of Extrication Fest, an international extrication school and expo held annually in Ft. Worth, Texas. He joined the fire service in 1964 and is a certified National Registry of Emergency Medical Technician. His other certifications include rope rescue, trench rescue, confined space rescue, and auto extrication; advanced firefighter certification, level II instructor; and Texas State Fireman’s and Fire Marshals’ Association training certification coordinator. He has completed such courses as Challenges for Training Officers and Public Education Leadership at the National Fire Academy. He is the author of The Rescuer’s Response to New Automotive Technology, a training manual, available from Fire Engineering Books & Videos this year.

 

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