NEW AUTO SAFETY TECHNOLOGY, PART 1

BY RON SHAW

Motor vehicle rescue can be one of the most rewarding and simultaneously one of the most challenging tasks that an emergency responder will confront in his career. Although the automotive industry has dramatically improved occupant safety over the past decade, in doing so it has unintentionally increased the risk for the responder. Today, more than ever, a responder needs to be wary of hidden hazards while performing vehicle rescue.

Obvious responder precautions are associated with avoiding the accidental deployment of active airbags during vehicle rescue. There are also the not-so-obvious supplemental restraint system (SRS) hazards to consider when cutting through undeployed inflators hidden in a roof pillar or behind the roof liner trim of the interior occupant cabin.

Newer airbags designed for side impact protection (SIP) may pose a concern for emergency workers performing vehicle rescue. This article offers responders a better understanding of how to recognize and safely mitigate SRS hazards in a vehicle rescue.


(1) The side impact curtain. (Photo courtesy of Ford Motor Company.)

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SENSATIONAL REPORTING

The news media recently have focused attention on airbag-related injuries to emergency responders resulting from the accidental deployment of unactivated SRS in vehicles at a crash. Discrepancies in published features on this topic seem to indicate reporters did not throroughly investigate the incidents; many of the stories are based on hearsay and are not well documented.

What airbag opponents and the media aren’t saying is that airbags have saved many lives and have averted serious injuries in accidents, compared to the relatively few occupant and responder nonlife-threatening injuries sustained. Of the injuries incurred by emergency workers, most could have been prevented with proper education and better standard operating procedures and guidelines (SOPs/SOGs). More importantly, the media have neglected to inform emergency responders about how they can improve safety while working with an undeployed but active (i.e., “live”) SRS to reduce the risk of an accidental deployment. Why not? Simply, this doesn’t sell news. Death and injuries sell news, not the lives saved by airbags.

As responders, we are responsible for adapting our extrication/rescue skills to address these new vehicle innovations..We need to adapt current rescue tactics to address new vehicle technologies.

DOCUMENTED RESPONDER INJURIES

Beginning with the injury of two Dayton, Ohio, firefighters in August 1995, airbags have drawn much attention. This was the first recorded incident of an airbag injury to emergency responders documented on video by a local TV film crew as the incident unfolded. Both firefighters were taken to the hospital and released later that day. They assisted in the making of an FETN video documentary of the Dayton incident to alert emergency responders about the hazards of vehicles with undeployed airbags at a crash. The training video was not designed to alarm or incite fear among responders but to inform responders of possible SRS concerns and to provide information that would reduce the risk of injury at a crash.

Fortunately, the two Dayton firefighters escaped serious injury. Had they been properly educated about airbags, the incident may never have occurred. Unfortunately, emergency responders often learn how to cope with new innovations after the fact. Since the Dayton incident, there have been approximately six documented nonlife-threatening responder airbag-related injuries. Six injuries were not serious enough to warrant the federal government to mandate new airbag legislation. One way for responders to reduce airbag injuries is through proper education.


(2) Side impact curtain system. (Photo courtesy of Ron Moore and Ron Shaw.)

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AUTOMAKER ERGs

The emergency services should learn about new vehicle systems before they appear on the road, not after an injury occurs. In addition, innovative vehicles may present other hazards of which responders should also be aware. Automakers are now more cooperative with the emergency services. For example, Toyota and Honda offer hybrid emergency response guides (ERGs) that provide responders with the comprehensive information needed to safely mitigate a rescue involving their hybrid electric/gasoline engine vehicles. Also, Volks-wagen and Audi have developed emergency services manuals for their conventionally powered vehicles.

VEHICLE EMERGENCY KILL SWITCHES

For years, the emergency services have suggested that the automobile industry install emergency kill switches that would disable a vehicle automatically or allow emergency personnel to manually disable it, eliminating possible hazards and related responder injuries. Some responders may feel that in the wake of recent negative coverage of airbags on national television, the industry or the federal government would be impelled to expedite settling this responder safety issue.

Most likely it won’t. To the contrary, the auto industry could easily demonstrate that the arguments of the group pressing for design changes are based on exaggerated reporting, not facts. The safety reasons presented for compelling the industry to implement a costly electrical engineering change in existing and future vehicles may be unfounded.

For example, if the automobile manufacturers voluntarily installed a kill switch/device in new vehicles, what might that imply about similar vehicles already on the road without this feature? In a liability lawsuit, could their good intentions be construed as implying that there are dangerous SRS hazards in passenger vehicles? It opens up Pandora’s box for legal issues that the industry obviously doesn’t want to create.

Having had the opportunity to work on both sides of the industry, I better understand the concerns and am more open-minded. Joint cooperation has gone a long way to improve the release of information involving these innovative vehicle safety systems for the use of emergency workers at a crash. Such cooperation would have been impossible if the emergency services were butting heads with the industry.


(3) Deployed IC during rollover crash test. (Photo courtesy of Ford Motor Company.)

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  • Although there have been accidental deaths involving airbag deployment, they are usually the result of occupants’ being improperly seated or unrestrained. Statistically, the number of airbag-related deaths is small compared with the large number of lives the airbags save. The causes of airbag mortality for occupants during a crash can be categorized as follows:
  • Infants improperly riding in the front seat;
  • Unrestrained occupants not wearing seatbelts;
  • Occupants wearing seatbelts improperly; and
  • Occupants within close proximity to airbags.

SRS CONCERNS

Not factored into government statistics is the emergency responder injured during a working rescue or training activity. Although there are no significant numbers, incidents have been documented in which responders have been injured while performing “routine” motor vehicle extrication tasks. These incidents have occurred during actual rescues or training with live-airbag equipped vehicles.

It should be noted that these incidents were accidental and might have been avoided with proper SRS education. Although injuries have occurred, there has never been a documented incident regarding a death or serious injury to any emergency worker that was a result of an accidental airbag deployment during a working rescue or while training.

Responder fear. Although concern for injury is real, responders should not develop a phenomenon I refer to as “responder fear.” This may develop in reaction to exaggerated news reports concerning new vehicle safety innovations that they do not understand or about which they lack the proper awareness. Responder fear can spread quickly through the emergency services community, especially through the Internet. Fear can be more real than the legitimate actual concern posed by the new innovation.

Responder fear often spawns unfounded stories causing unwarranted concern throughout the emergency services. One example is the recurring “Slim Jim” hoax. Allegedly, a police officer is killed while trying to unlock a vehicle door equipped with side impact protection (SIP). As a result of the widespread Slim Jim warning (hoax), many responders who normally would have provided this type of service refused, fearing that they, too, might become the next airbag victim.

This alleged incident never happened, nor is it even possible. When an unfounded story like this hits the Internet, it spreads like wildfire, causing unwarranted concern among emergency responders. Unfortunately, on seeing such a story in print, responders may take it as factual information and unknowingly pass this misinformation along. Had the responder been properly educated, he might have questioned the validity of the story. This lack of information is not always the fault of the responders or their agencies. The automobile industry as a whole needs to work more closely with the emergency services and provide accurate information on the latest vehicle features prior to their introduction.

Some industry leaders, such as Toyota, are working with responders to ensure safety at an incident involving innovative vehicles. When properly educated, responders should be able to safely mitigate a motor vehicle rescue without compromising their safety or that of a patient.


(4) Typical IC hybrid pressurized gas inflator. (Photo courtesy of Extrication.Com.)

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RECENT SRS INNOVATIONS

The side impact curtain (IC) is one of the latest innovations offered by the auto industry for side impact and rollover protection. Side impact protection systems (SIPS) react more quickly and deploy more forcefully than frontal restraint systems because of the shorter distance between the point of impact and the occupant. Impact curtains are stored along the outer roof rails in the interior of the occupant cabin. These long and narrow-width airbags deploy from behind the trim along the roof liner downward, covering the side windows to the bottom of the window frame or windowsill of the door (photos 1, 2, and 3).

How the IC system works. Typically, the side impact curtain activates as a result of a side impact (collision) or a rollover. The IC system is equipped with individual electronic crash sensors for both driver and passenger side curtains. The sensors are typically located near the base of each B-pillar and act independently of each other. If the crash is severe enough, the sensors will only open the electric circuit on the impact side of the vehicle. On the opposite side of the vehicle, the SIP will not be activated until acted on by a secondary crash or rollover. Open sensor circuits will allow the electric current to flow back to the SRS controller. The controller then transmits a low-voltage electric current to the appropriate side IC inflator (gas generator). The inflator produces large volumes of cool/hot-pressurized inert gases that fill the appropriate IC during the deployment stage. Hybrid inflators are currently the most popular IC gas generator used by the automotive industry.

How hybrid inflators work. The electric impulse received from the SRS controller (electric control unit) ignites a chemical initiator, which ignites an extruded propellant. The resulting pressure wave ruptures a burst disk on both sides of the pressure vessel, liberated liquefied compressed gases quickly vaporize back into the gaseous state and exit through a diffuser (perforated/slotted end cap) on the airbag/curtain side of the inflator. The hidden curtain (with a series of vertical baffles) rapidly fills and deploys across and downward through the bottom of the interior roof trim. The bottom of the roof liner trim is left unrestrained to allow curtain deployment (photo 4).


IC inflators (one or more together in a line or on opposite sides of the vehicle) are hidden behind the interior roof/pillar trim/molding. (See Figure 1; numbers in parentheses refer to location in illustration.) The most common IC inflator locations for current model vehicles are as follows:

  • Midpoint in driver and passenger side rear pillars (1).
  • Above the driver and passenger side B-pillars in the roof rail (2).
  • Above the driver and passenger side rear pillar at the roof rails (3).
  • Midpoint above the rear lift/hatch gate/door in the rear roof rail (4).
  • Left and right of the rear pillar above the rear lift hatch/door on both driver and passenger sides (5).

Responder cautions. Pressure vessels in hybrid inflators will have a stored gas static pressure ranging from 3,000 psi to more than 4,000 psi. It is possible that responders could inadvertently breach (rupture) a hidden side impact inflator while displacing or removing a roof. To the uneducated or foolish, cutting into the pressure vessel of an undeployed pressurized gas inflator could fracture the tool’s cutting blade(s) or cause projectiles to fly. Cutting into the curtain bag of an undeployed SIPS provides an open avenue for unrestrained hot pressurized gases to blast through. Avoid cutting into an undeployed airbag system—serious injuries could result!

When technicians replace spent or problem airbag inflators, they disconnect the wiring harness connector to the inflators. This causes an internal shunting device to ground out the electrical circuit, thus preventing an electrostatic charge from entering the circuit and activating the inflator. Cutting into the area of any inflator could cut the wire harness and provide an open avenue for an electrostatic charge to ignite the IC inflator. Whenever possible, responders should avoid cutting into any wiring harness of any supplemental restraint airbag system.

IMPLICATIONS

Modern vehicles have hidden safety devices that can cause injury to rescue personnel during motor vehicle rescue. It is important for responders not to rush into a situation without first performing a proper scene size-up and, if required, a risk analysis to weigh the options. Do not let good judgment be clouded by your reaction to the severity of a crash.

Emergency responders know that cutting sheet metal with heavy rescue tools is similar to cutting paper with scissors. However, what they may not know is when heavy rescue tools breach hard steel objects such as the pressure vessel of a pressurized gas inflator, cutting does not actually occur. Heavy rescue cutting tools don’t slice through hard steel. What actually occurs is that the tool’s cutting blades compress the hard metal to the point that the material fractures, resulting in a failure of the pressure vessel.

When the pressure vessel of a nondeployed pressurized gas inflator is breached in this manner, there will be a catastrophic failure. Should this happen, there will be a sudden rapid release of the stored compressed liquefied gases that will cause projectiles when the two ends are unrestrained. It should be noted that a catastrophic failure would occur only when the pressure vessel is compressed, causing metal to fatigue and fracture. Pressurized gas inflators use a stored pressurized static gas pressure of 3,000 to more than 4,000 psi, close to the operating pressure of a hydraulic power unit. With the tremendous kinetic energy that is available, the responder should understand that the pieces of the dismembered pressure vessel left unrestrained could become projectiles.

Besides the possibility of projectiles, hidden hard steel components in the normal structural cut zones can also damage heavy rescue cutting tools. For this reason, it is important that responders know the limitations of their tools. Recognize that if the cutting blades encounter excessive pressure or are side loaded because of twisting, the blades can fracture.

Cutting the SRS wiring harness can allow an electrostatic discharge (ESD) to enter the circuitry and activate the nondeployed SRS devices. Caution should be used when cutting into the area of the SRS components or wiring harness to avoid the accidental deployment of an SRS. When required to cut the SRS wiring, ensure that victims and personnel are not within the deployment path of the active airbag.

Emergency responders should now realize that it is important not to rush into an incident without first scanning the rescue area and vehicle(s) to recognize and identify existing and potential hazards including hidden nondeployed SRS. One way to recognize the impact curtain airbag is to scan the vehicle’s occupant cabin looking for airbag icons indicating the presence of nondeployed airbags. Typically they are identified by the lettering “IC” or “Airbags.” If required to cut into these areas, the responder should pry back the interior trim to locate the inflator or wiring or seek an alternative method to execute the rescue.

Hybrid/pressurized gas inflators used for impact curtain airbags have a pressure vessel filled with inert gases pressurized up to 4,000 psi or more. When the pressure vessel casing is breached or fractured, it can catastrophically fail, causing the loose ends to become projectiles. Cutting into an undeployed IC airbag will provide an avenue for pressurized gases to flow unrestricted, increasing the risk of injury from the open butt end. Whenever possible, avoid cutting into the structural area where the SRS components are located.

RON SHAW is a lieutenant with the Plymouth (MA) Fire Department. He is the founder of Extrication.Com, which provides training and online safety information concerning motor vehicle rescue/extrication. Shaw is currently compiling the Extrication.Com Vehicle Extrication: Basic Skills textbook for Jones and Bartlett Publishers.

Safety Notes: Whenever possible, responders should avoid cutting into the area of any SRS components, especially compressed gas inflators. Areas that may conceal active airbag inflators should be considered a cutting “hot zone”—the responder should use extreme caution when cutting near or into these areas. Never try to restrain an active airbag—serious injury or death may result! Avoid cutting the SRS wiring harness whenever possible to avoid an electrostatic discharge to activate an airbag.

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