From the vehicle extrication e-Newsletter, sponsored by
By Bob Pitman
The changes we are seeing in automobiles are astronomical. I remember when having a car with a headliner was a luxury. Fifteen years ago, we had no idea of what air bags were or that we would some day be worrying about their hurting us after a crash. Now we some certain high-end vehicles that can have up to 16 airbags in them, none of which deploy if the car is hit from the rear.
It used to be that new model vehicles came out once a year, around October. Now, new vehicles are coming out quarterly, and supplemental restraint technology is changing just as quickly. I doubt there is any way for firefighters in most parts of the country to keep up with what is driving through their areas. Just as a thinking exercise, remember 1998: BMW came out with its head-protection system air bag that year. In 1999, Volvo and Mercedes worked together and came out with the first side-curtain air-bag system. Seven years later, in 2006, side curtains were available in more than 280 models of vehicles and the federal government was pushing for them to become standard equipment. The curtains work on stored gas cylinders. For a long time, you knew that the cylinder was going to be in the A post or rear post, and was going to be under 3,000 psi of stored gas pressure.
Components
Nowadays, cylinders may be located all around the roof posts and perimeter rails of the vehicles. They may contain up to 9,500 psi of stored gas pressure. The only tests done so far that actually cut these cylinders under pressure says simply that the cylinders fail with “catastrophic” results. I firmly believe that these cylinders will either kill a firefighter or put a fire department out of business in the near future. The going-out-of-business will be the result of a negligence lawsuit when we cut one of these cylinders and the shrapnel kills the victim in the car. The 2007 Mercedes MB S class has safe cutting zones marked on the posts to aid rescuers in removing occupants. You can find this information on the Mercedes Benz Web site under “rescue.”
Also, little is known about seat belt pretensioning devices, which are often not noticed. They are nearly standard on every vehicle that has two front air bags, which have been federally mandated since the late 1990s. These devices employ a pyrotechnic device located on on the seat-belt retractor or the seat-belt receptor end. Once sensors tell the air bags to fire, the pyrotechnic device engages and takes four to six inches of slack out of the seat belt before the air bags deploy, pulling the occupant into proper sitting position to be struck by the air bag. They often cause serious abrasions to the occupant’s chest, and occasionally fracture ribs or collar bones. If the car is hit in the side or rear, these items do not fire and remain live, possibly in your cutting zone.
Smart seats/bags can present issues for us as well. These systems have double sensors, wired in series. The sensors can activate the air bag brain and tell it to fire the frontal air bags. The brain then reads the seat sensors in the passenger seat to find out if someone is sitting there. If there is, the sensor may fire the bag. If no one is there, the sensor does not fire the bag. In such a scenario, the air bag brain wants to fire the passenger bag but does not because there was no weight on the seat. If a responder then comes along and plops down in the passenger seat to assess the driver, there is an outside possibility that this extra weight could deploy the air bag. Most of these bags are also dual stage, meaning that they can fire twice. If a child or very small adult is in the passenger seat, the bag may only fire in low-pressure mode. Imagine: You arrive to find the bag hanging out of the dash and assume everything is okay. Ignoring all the multiple-language warning notices on the bag, including the English warning, you miss the message: “Warning–treat this bag as unfired.” This seat sensor weighs the occupant and adjusts its firing to their weight, but it can literally fire again, refilling the same bag with air at 200 miles per hour. I would not want to be sitting in this seat assessing the driver when that happens.
With all of the systems, the priority is to find and disconnect the electrical system. This is more easily said than done these days, with batteries situated in different parts of the vehicles. Use the electrical system to your advantage before disconnecting it: Unlock doors, move seats out of air-bag deployment zones, and roll windows down before you cut the battery. But, be careful performing these tasks if they involve placing yourself in the deployment zone of an unfired airbag. Our department now performs these actions first and disconnects the battery afterwards. We then stabilize the vehicle, perform glass control, and strip the plastic trim off the posts to check for cylinders. Taking time to do this gives the air-bag brain capacitors time to drain and lessen the possibility of accidental deployment.
Extrication
The extrication problem has become more difficult as well. When you are dealing with a disposable car with plastic side panels, what do you pry against? As time goes by, I think you will find hydraulic cutters replacing the spreaders as the initial tool of choice. With the structural steel components now being made of exotic steels and alloys, our old cutters that cut at 40 to 60 thousand psi of cutting force will often not make the cut. One company has recently introduced a set of cutters that can grip a basketball and close with a cutting force in excess of 300,000 psi to deal with today’s car metals. One of the things our department has begun doing to avoid unfired air bags is to use the back doors. If passengers are in the front seats and those doors are jammed, or if the person is sitting behind the B post (pretty common these days), we open the back door, lay down the bucket seat, slide a backboard down the back of the seat between the seat and the patient, and then slide the patient up the board and remove the board from the vehicle. This keeps you out of the frontal bag deployment zones and works as well as anything else we have tried, although it does not work very well with extremely large patients.
Hybrids
Hybrid vehicles are becoming more popular, especially with gas prices going up, and I think we all know that fuel prices are going to continue to rise. Hybrids use a combination of an electric motor for low-speed driving and/or low-end power, supplementing that with a gasoline or diesel engine for high-speed driving (depending on the setup of the vehicle). Around five years ago, there were only three hybrid vehicles: The Honda Insight and Toyota Prius were all-time hybrids, and the Honda Civic could be ordered as a hybrid. Now there are at least 13 hybrids on the road, with more on the way.
The current hybrids can be listed as one of three types: full hybrid, parallel hybrid, or partial Hybrid. The full hybrids can run off of the electric motor, the fueled engine, or both simultaneously. They seem to be the most fuel efficient. The parallel hybrids use the fueled engine to drive the wheels, then use the electric motor for extra power when needed. The partial hybrids use a large electric motor to replace the starter and associated parts of the vehicle. Keep in mind that most of these vehicles will move like an electric golf cart–you will never hear a sound, but the vehicle will be off and running.
When working with hybrid vehicles after a crash, I use a memory aid: the hybrid “IS A TOAD.”
- I – Identify vehicle as a hybrid
- S – Stabilize to avoid rolling (vertical / horizontal – chock the wheels early)
- A – Access your patient
- T – Transmission needs to be put in park
- O – Off (Make sure the key is turned off and gone)
- A – Assure the ready (green) light goes off
- D – Disconnect the 12-volt battery after using the electricity to your advantage. Most manufacturers claim that disconnecting the 12-volt electrical system will shut down all of the high-voltage components as well.
Another concern is the “proximity” key. This key allows the vehicle to be started and run without a key ever being placed in the vehicle. As long as the key holder is within 30 feet or so, the vehicle will run. You need to obtain the proximity key from the victim and get it away from the vehicle to assure shutdown.
Hydrogen-electric hybrids and hydrogen-fuel cell vehicles are another issue we will be facing in the near future. The hydrogen electric-hybrids are already around; the State of Florida has recently ordered several of them for use in one of the state parks. Florida’s first hydrogen filling station opened near the Orlando airport recently. It is for filling hybrid buses that are going to be used as airport shuttles. Florida will open a second station as soon as feasible in the Oveido area. California has several hydrogen filling stations up and running. This is not a far-fetched concept; it is here and gaining momentum. It has been reported that GM and BMW are working together on a cryogenic, liquid hydrogen, internal combustion engine project. On another note, the State of Florida Department of Environmental Protection has purchased 12 hydrogen-electric emergency generators for use at its major facilities throughout the state. The company that sold these to Florida claims that in 10 to 15 years, they will be able to put them in our yards to permanently run our homes.
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Bob Pitman has worked with the City of Bartow (FL) Fire Department for nearly 29 years. He has worked his way up from recruit firefighter to his current position of deputy chief of training, and holds many State of Florida and national certifications. |
