“The cars we are cutting up in the junk yards aren’t the cars that are crashing on the highway”
This is the first of two articles on new car technology. Firefighters in the fire service today have more demands placed on them than ever before. We must know about lightweight truss construction, rapid intervention teams, saving our own and now weapons of mass destruction. While I believe this is very valuable training and certainly important to the fire service, I also believe the knowledge skills and abilities associated with vehicle extrication have not kept pace with the technology of the auto industry.
Back in the 1970’s the big buzzword in the fire service was extrication and EMS, in the 1980’s it was Haz Mat, in the 1990’s it was Technical Rescue, now we have WMD. With the way the auto industry has changed the safety features of cars today, I think it is time we revisit vehicle extrication.
During the past several years I have been teaching auto extrication to fire departments, I have learned a few things, one is most departments have little knowledge of new car technology as it pertains to vehicle extrication and they are using antiquated techniques taught when they first joined the fire service.
Sure everyone knows that cars today have airbags in them, but do you know how to avoid them and still perform an extrication without injuring yourself or the patient? Are you aware of the new types of steel auto makers are using in the cars on the road today? Do you know if your cutters have the capacity to cut a triple rolled high strength low alloy steel A post?
In this article we will take a look at some of the new car technology as it pertains to vehicle extrication. We will talk about some of the different types of steel used by the auto makers today. We will also look at seat belt pretensioners and the different types of airbags we may encounter.
Types of steel used in vehicle construction
In today’s autos you will find a wide variety of steel used to construct these vehicles. There are Mild Steel, High Strength-Low Alloy Steel, Ultra High Strength Steel, Cast Magnesium and now we are running into Boron Steel tubes in the A-post.
Auto manufacturers are using more high strength steels in their operation than ever before. The main reason is they can use thinner metals and get greater strengths. High Strength low alloy steels provide greater strength with less mass and that in turn provides as much as a 30% weight reduction as compared to mild steels. High strength steels also absorb more energy per pound than mild steels making them more crash worthy.
Manufacturers are placing crumple zones into this high strength steel. These body parts are designed to crumple in a predetermined pattern to absorb the energy produced during a collision while maintaining the integrity of the passenger compartment.
One question I want you to ask yourself as you read about the different types of steel is, “Can my extrication equipment do what is needed on these newer cars?” If you don’t know, research the data on your existing equipment. Find out what your spreaders, cutters and rams are capable of doing.
We took a good look at this a few years ago on my fire department and found that our equipment would not meet the challenges newer cars present. It had taken us two years to convince the Mayor to allow us to purchase new tools. My point here is, is even though you read this article and go out and get more education on new car technology and extrication, change is slow. Don’t get discouraged if your request for new equipment is denied at first. Keep after it with more and more supporting documentation and hopefully it will happen. Extrication seems to have taken a backseat to all of the other things we need to learn and do as firefighters. The way the auto industry is building cars now, it is forcing us bring auto extrication to the forefront again.
Mild steels are the softer steels that most of us are familiar with when it comes to vehicle extrication. The most common areas we find this type of steel is in the rocker panels, floor pans, quarter panels and fenders. This type of steel will cut very easily and when we use our spreaders and rams, we don’t often have trouble moving this type of steel. Generally most people have problems when they attempt to use mild steel as a hard push point. This steel will move before the object they intended to move and the operator will not achieve the result they desired. These areas should be considered soft push points during your extrication.
High Strength Steel
This type of steel has relatively the same qualities of the mild steel. Some of the uses are in the hoods, door skins and quarter panels.
High Strength – Low Alloy Steel
This type of steel is used in the construction of the pillar posts, side members, front and upper rails and the shock tower supports. These types of steel have high tensile strengths and are used to give the auto support. When used in the A,B and C pillar posts, it gives the car better rollover protection and helps keep the roof from collapsing in on the occupants.
High Strength – Low alloy steel will be harder to move with our spreader and ram (see picture 1 above). These areas will work well as hard push points during your extrication. Older cutters may not have the capacity to cut a triple rolled high strength low alloy steel A or B post.
Ultra High Strength Steel
Ultra high strength steels have incredibly high tensile strengths, some have upwards of 180,000 psi tensile strength. You will find this type of steel in the side impact door beams, reinforcement bars under the dash and bumper reinforcements. Only attempt to cut this type of steel if it is absolutely necessary it may fragment (see picture 2 above).
Look at the size and shape of the older style side impact protection system in the photo above right. There have been cases during off center front end collisions where the side impact beam will pierce the door and lodge itself into the B-post. This acts just like the deadbolt on your door at home. You will not be able to open the door with your spreaders if this happens. Your best bet to get this door open is to start on the hinge side, cut the hinges and attempt to remove the door from there.
New Style Side Impact Protection
Picture 3 below reflects a newer designed side impact protection system. This newer design protects the occupants with three separate protection systems. The first is an ultra high strength beam running through the middle of the door. The second is a boron steel insert at the top of the door and the third is a honeycomb section at the bottom of the door.
Car manufacturers are now using boron tubes in the A-posts of some vehicles. These boron tubes can have tensile strengths as high as 150,000 psi. There have been cases where fire departments attempted to cut the A-post with older style cutters and were unsuccessful.
What they found after researching this further was a boron tube placed inside the A-post to give the A-post added strength during a rollover type accident (see picture 4 below).
With all of the new techniques that are being taught today, the cutter is most used tool you will carry. When I first started in the fire service years ago, we were taught to spread everything and cutting was something you rarely did. Today you will use your cutter 60% – 70 % of the time. You need to have a large capacity cutter in your arsenal that will do the work necessary on today’s vehicles.
Picture 5 below shows the Hurst MOC cutter cutting the boron steel A-post. Notice in the photo that the Hurst cutter is able to cut this boron tube in the center of the blade. This is very important, other manufacturers say they are able to cut a boron tube but it has to be cut at the notch located at the rear of the blades. With the larger diameter of this boron tube and the triple rolled steel surrounding the tube, you may not be able to make your cut at the notch. Be wary of claims made by any manufacturer and test this equipment yourself before you purchase it. There are tests that NFPA has established for cutters, educate yourself on these tests and require your equipment manufacturer to perform these tests at their demonstration. There are different levels of criteria for cutters, require the cutter you choose to pass the highest levels established by NFPA. Remember, your cutters are going to be doing the majority of the work on newer cars. Demand the best equipment available for your fire department.
Some car manufacturers are using cast magnesium in the transverse dash beams. It runs from one side of the car to the other near the top of the dash area. Auto manufacturers are using these to give the car more lateral stability and they are using them to hang all of the components on the dash. This helps us when we are doing a dash roll up because all of the components move with the beam. One of the drawbacks to this technology is during a car fire. The amount of magnesium used in this technology isn’t a lot but we all know what happens when we put water on magnesium as it burns.
For more information, go to www.footagerescue.com