MODERN VEHICLES: CHALLENGES AND CONCERNS

BY DAVE DALRYMPLE

Today’s motor vehicles challenge the emergency responder and pose many concerns. Each type of vehicle—be it a car, a pickup truck, an SUV, or a minivan—presents issues specific to that vehicle. Some of them are also similar in some ways. Although much of the focus on vehicles centers on safety systems such as airbags, we need to be aware of many other components, materials, and systems. And, we need to take into account not just motor vehicle crashes but also vehicle fires and even the “simple” medical response to an individual in a vehicle. To keep pace with the ever-changing components and features of these vehicles, we must keep updating our background knowledge.

CONSTRUCTION

Most vehicles today are built with a unibody configuration. This type of construction is strong and lightweight and is built around the concept of structural integrity—all its components must be intact. So, when we remove or displace any of the vehicle’s components (doors, side, roof, and so on) or if they are displaced by the crash, the vehicle’s integrity is weakened. This can help or hinder us. The key point here is to consider this in our action plan as we perform our tool evolutions to create space within which to work to extricate the victim.

Let’s look at the energy absorption areas (read: crumple zones) in the vehicle. Throughout the vehicle are engineered areas designed to absorb energy (crush) during a crash; however, the largest area, and the one that has the greatest impact on us as responders, is the vehicle front. Think about some of the crashes you responded to recently, especially those with front-end impacts. Where does the vehicle’s nose go? As the vehicle absorbs crash energy, the nose of the vehicle compresses, the engine/drivetrain drops downward, and many times the front tires are forcibly deflated. This basically places the nose of the vehicle onto the ground. If the front of the vehicle is on the ground and the basis of the dash roll evolution is to “lever” the dash forward and upward, how effective will this tool evolution be?

Now, add into this mix the significant reinforcement built into the dash area. This reinforcement has gained significant strength (read: high-strength steels/alloys) over the recent past. As you can see, the reinforcement is “tied” not only to the vehicle’s sides but also to the floor and forward to the firewall. So coupling the issue of crush zones with dash reinforcements, I ask again, How effective will a dash roll evolution be?

Maybe we need to rethink how we perform dash displacements. Instead of rolling the dash forward, perhaps a vertical lift of the dash would be more in order. Also, what if we placed another relief cut to assist our dash displacement in a new location? We already make relief cut(s) into the lower dash/A-post area to allow the dash to move, so let’s consider now a relief cut to make a “hinge” point for the dash—to not only move but to pivot as well.

The relief cut might look like a cut into the fender; the concept for the evolution is to “sever” the crush zone area behind the fender, thus allowing the dash area to move “independently” of the rest of the vehicle when displaced. Therefore, even if the nose of the vehicle is on the ground, you will be able to displace the dash effectively.


(1) Subaru WRX dash reinforcement bar. (Adapted from Subaru art.)

null

REINFORCEMENTS

Since we’ve touched on reinforcements, let’s delve into this area a little further. Although many of today’s vehicles are made of lighter-weight materials than in the past, many more are reinforced with alternative materials and methodology. More points of reinforcement are found today. Also, there is a greater percentage of high-strength steels (HSS). Some vehicles have more than 63 percent of high-strength steel/alloys. Many of these alloys, such as boron or micro-alloy steel, are very difficult to cut, even with power hydraulic cutters. Even some vehicle components and reinforcements are constructed of these materials. Imagine what might occur if a door side impact bar were displaced forward or rearward. Most of these components are made of either material. Now imagine trying to sever the roof posts of Volvo’s XC90 SUV; these posts are predominantly constructed with boron steel. Food for thought.

Another popular reinforcement in today’s vehicles is “blown-in” polyester foam. Much akin to foam used to fill cracks and voids, this material adds much to the structural integrity of the vehicle without adding significant weight. However, think about what this material will do when you are trying to sever it with a powered hydraulic cutter or reciprocating saw! What kind of fire load will this vehicle have if it’s on fire? This material makes tool evolutions difficult, because of the additional force needed to compress and then shear (powered hydraulic cutter) or the blade’s becoming dull and gummed up as the material adheres to it (reciprocating saw).

In terms of fire, the amount of plastics in vehicles today is significant even before you add in the large percentage of the vehicle’s structural voids that are filled with plastic. Also, certain components, because of their locations, have been given “extra duty” by changing their configurations and materials.

The seat belt attachment/bracket on the B-post is the best example of this type of reinforcement. Since most seat belt attachment points on the B-post are adjustable, they are in the perfect location to reinforce the upper B-post area.


(2) Creating the fender hinge. (Adapted from Pontiac-Grand Prix art.)

null


(3) Fender hinge evolution. (Adapted from Opel-Kadett art.)

null

DOOR DISPLACEMENT

With all these construction concerns, what about our door displacement evolutions? Is just popping the door enough? Is it easier to pop the door today than in the past? I would say it is more difficult. Maybe we have to move toward a side removal and away from a door pop. Using our knowledge of the vehicle’s construction, we look for weaker areas and new pathways to displace—such as a B-post tear/rip evolution.

WINDOWS

Let’s look at windows. Think of the various types of glass or glazing in use. The two types of glass to which we have become accustomed, laminated and tempered safety glass, are still the most widely used, but a few new “curves” are out there. Enhanced protective glass, or EPG, is basically a format of laminated glass placed in the side and rear windows. Dual-paned glass and polycarbonate glazing are also used. Some of these materials necessitate that we change our methodology and tools for removing windows.

Also, add dust masks to your personal protective equipment for glass management, and factor in the rear glass hatches in SUVs and minivans. These glass hatches have a nasty habit of flying apart when broken because of the tension placed on them by the multiple hatch struts and the distortion of the vehicle’s body during the crash.

BATTERIES

We will soon see the end of 12-volt electrical systems. Today’s vehicles have so much technology that the existing 12-volt systems cannot keep up with the demands. However, voltage is not the greatest concern; the difficulty is finding the battery. Moreover, it is possible that there are alternative power sources in the vehicle. You must disconnect both battery cables to disarm and drain the energy storage system for the vehicle’s safety system(s).

GAS STRUTS

Gas struts in hatches have been a concern for quite awhile. However, these devices have found their way into other locations as well. We still need to use caution when working around hatches, especially on SUVs and minivans, because of glass-management issues. If we cut through the hatch, it is possible that the strut may suddenly extend the “stub” of the hatch outward. Some of these devices can be longer than three feet and also can be found in trunk lids and side doors in some vehicles.

We must be especially careful when working in the engine compartment at vehicle fires. The gas struts can “cook off” and take flight, leave the engine compartment, and fly up to 250 feet away from the vehicle. They have been reported to have caused serious shrapnel-related and impalement injuries.

ALTERNATIVE POWER SOURCE

The high-voltage systems in gasoline-electric hybrid vehicles also pose concerns. The ERG (emergency response guide) for each vehicle can be downloaded from the manufacturer’s Web site [www.toyota.com (Prius) and www.honda.com-look (Insight and Civic IMA), for example]. The ERG reviews a wide variety of issues and concerns and contains background information for emergency responders. One item I wish to highlight is that these vehicles may be “running” without making any noise, depending on the charge state of the high-voltage battery pack. This year, we will see two hybrid SUV models, the Ford Escape and the Lexus RX-300, as well as the next generation of the Toyota Prius. The next Prius will be a much larger vehicle with a system of approximately 500 volts.


(4) Audi side curtain inflation module –C-post. (Adapted from Audi art.)

null


(5) 2003 Mercedes-Benz E Class side curtain inflation module, A-post. (Adapted from Mercedes-Benz art.)

null

SAFETY SYSTEMS

We have become accustomed to frontal SRS systems; however, we should look at them more closely. Generally, if an airbag were deployed in the past, it was considered spent. Many vehicles today are equipped with dual-stage frontal SRS systems. Basically, this means the system has two inflation modules, a module designed to deploy at a lower speed/impact and a second for a higher rate of speed and crash severity. Also, a high-speed impact usually deploys both modules. Now the issue is, How do we know which module(s) have deployed? We can’t tell by observation.

One manufacturer believes such systems are enough of an added concern for responders that it has provided a warning label on its dual-stage airbags. These systems can be found across the board in many vehicles of varied types and brands. Disconnecting the battery will drain the energy storage system in the airbag computer, but other energy (an alternate power source or static electricity, for example) might interact with the system.

Many large vehicles are equipped with frontal SRS systems. In fact, one manufacturer has provided some of its models with inflatable tubular systems (a head protection airbag) and even seat belt pretensioners. Think about disarming the battery system in these vehicles!

Side Safety Systems

These systems are becoming more prevalent. They have expanded from the Volvo seat-mounted system in 1995 to a door-mounted system and then to a rear-seat and door-mounted system. Now, we have head-thorax side systems and roof rail/side curtain head protection systems. Many of these side systems are multichambered to give additional protection to the occupant’s side and head. Side-curtain systems protect the head and give added protection during a rollover, keeping the occupants inside the vehicle. Disconnecting the battery to drain the energy storage system will help us to ensure a safe working environment. However, we must keep in mind the following:

  • Some side systems are mechanically activated; disarming the battery will not make these systems safe.
  • Certain mechanical systems have emergency guides for disarming them.
  • When operating power hydraulic tools in close proximity to these side systems, be extremely cautious, especially when the systems are not deployed. When you perform door and side tool evolutions, do you put yourself in the path of undeployed side systems? Are you careful about where you place your tools during these evolutions? Side Curtain/Head Protection Systems

A few years ago, only a handful of vehicles had these systems. Now, they can be found in more than 186 models across all types of vehicles. The bag part of these systems is benign; the inflation system is of concern. The nature of the system is that it needs to react and deploy in one-third of the time as the frontal SRS system. The inflation module is a pressure vessel topped with a small pyrotechnic charge. The gas stored in the module is an inert gas, but it is stored at approximately 3,000 psi; higher-psi and larger-volume module systems are just around the corner. Think about what might happen if you cut through one of these devices if it were undeployed. At a minimum, there would be a release of high-pressure gas in close proximity to the tool operator and possibly the interior rescuer and even the patient(s). The worst-case scenario would be deployment of the side curtain inflation module coupled with the release of high-pressure gas. There is also the potential for creating debris and even shrapnel. You must avoid cutting these devices. Even disconnecting the battery and disarming the system electrically will not help if you cut through the device.

Where are these inflation devices located? A few years ago, the inflation device was in the rear roof post. In 2002, that all changed. It now can be found in any of the roof posts, the roof structure itself, or even the vehicle body.

How do we find the inflation devices? How do we know in which vehicles to look for them? One clue would be if one of the side curtains were deployed. Another would be if the vehicle were a recent and high-end model. These facts should at least alert us to use more caution when dealing with roof posts. However, the best and surest approach is to strip interior trim before cutting the roof posts. You don’t have to remove the trim completely, just enough so you can move the trim away and see the roof post structure and ensure a side curtain module is not mounted there. Remember though, this does not apply to the models with these devices in the roof structure or the body.

What do you do if you find such a device? Ensure that you have disconnected the vehicle’s battery to isolate the electrical power. Try to sever the roof post below the module if at all possible. If you cannot, cut the post well above the top of the module to ensure you do not cut through the pyrotechnic charge. The bottom line is, these systems are a very real concern for emergency responders and should be treated with caution.


(6) Mercedes-Benz dual-stage airbag warning labeling. (Adapted from Mercedes-Benz art.)

null


(7) 2003 Honda Accord side curtain module. (Adapted from Honda art.)

null


(8) Side curtain inflation module roof structure. (Adapted from Audi art.)

null

SEAT BELT PRETENSIONERS

Seat belt pretensioners are powered devices that remove slack from the seat belt, ensuring that the occupant is seated properly when the airbag system(s) deploy. They are usually powered by a pyrotechnic charge; some are powered by a gas cylinder and even high-torque electric motors. These devices are used in all seating positions, front and rear, in almost all vehicles. These devices are fairly benign to the rescuer, but it is a good idea to ensure that you cut the seat belts when working close to the belt. Even if you disarm the pretensioner by disconnecting the battery (just as with airbag systems), there is the potential for accidental deployment. Avoid cutting through these devices during tool evolutions, especially in the area of the B-post.

Let’s consider the new locations in which we might find safety systems. We have had knee airbag systems since 1998 with the Kia Sportage; however, we now can find such systems in the BMW 7 series and the Audi A8. These systems need careful attention when performing dash displacement evolutions. In the future, look for new systems in the rear seat belts, head rests, and the seat cushion itself, among other systems.

Construction, materials, and components will affect our rescue efforts more and more as time progresses. We will need to review our methodology and tool evolutions more often and in conjunction with all vehicle concerns. We will need more background information about vehicles and their components. Knowledge is key to our efforts, our ability to make change and to push the envelope when needed. Also, remember safety systems are becoming more widespread and comprehensive.

Think about training issues and concerns: What do we get to practice on today? Is it a fair comment to say the vehicles we encounter are much different from those on which we practice? Okay, if we can’t get the vehicles, can we simulate some of the hazards, issues, and concerns? The bottom line is this: Rescue teams need to think and work smart when presented with issues and concerns associated with contemporary vehicles.

DAVE DALRYMPLE is a career EMS provider for the RWJUH Emergency Medical Services in New Brunswick, New Jersey, and a volunteer firefighter/EMT/rescue technician for Clinton (NJ) EMS/Rescue. He has been actively involved with emergency services for 20 years and a transportation rescue instructor for more than 14 years. He is a certified New Jersey fire service instructor, the lead instructor for vehicle rescue programs at the Hunterdon County Emergency Services Training Center and the Somerset County Emergency Services Training Academy, and an ICET-certified and registered international instructor. Dalrymple is the education chair of the International Association of Fire Chiefs Transportation Emergency Rescue Committee (TERC), a certified international level extrication assessor, and road traffic accident adviser on the Expert Technical Advisory Board of the IETRI.

No posts to display