BY DAVE DALRYMPLE
Let’s consider cutting evolu– tions. What kind of vehicle components do we have to sever today, and what tools and operations do we use? More important, how effective are these operations today? With the new materials and construction used in contemporary vehicles, we must reevaluate our tools and look at the evolutions we have learned in a new light (photo 1).
 Photos 1, 2, 4, 5, 8, and 11 by Denyel Cusimano. Photo 3 courtesy of Jorg Heck. Photos 6, 7, 9, 10, and 12 by author. |
Think back to your first extrication class. To remove doors, the focus was on “popping” the door off by spreading the door away and off the vehicle from both the hinges and the latch. Since the cutters used then were unable to cut either of these components, we used the spreader techniques to remove doors. We used the cutter to make relief cuts for making a dash roll and to sever roof posts. Think of how much stress and strain door pops put on the vehicle, the victim, and the rescuer. With roof post cuts, except for placing the cut at a 90-degree angle to the roof post and making either “pie” or “scissor” cuts, little technique was involved. It wasn’t as critical as it is today (photo 2).
But in today’s cars, door pops actually shred and tear the door materials, leaving us little choice but to cut the hardened hinges and latches. Vehicle roofs and roof posts now have ultra-high-strength reinforcements and side curtain airbag systems, so how easy are those post cuts? Can your cutter actually sever those ultra-high-strength reinforcements? The 2007 Mercedes Benz S Class has the world’s first cut markings printed right onto the “A” and “C” post areas (photo 3).
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Can your cutter perform strategic cutting, such as severing crumple zones? Many other tool evolutions now revolve around cuts and cutting, more than in the past, and we will have to rely more on cutting in the future. Most power hydraulic tool manufacturers have at least one cutter that provides more than 100,000 pounds of cutting force. They regularly test their tools on new vehicle components and other hardened materials and know that this will be the trend in vehicle manufacturing.
What kind of a cutter do we look for? We need one that can cut ultra-high-strength materials and open fairly wide (at least nine inches) and has a blade design that can handle hardened and lightweight materials well.
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Take a look at the cutter’s blades. Straight-blade cutters usually have two points of contact to grab the item to be cut. Such cutters cut like a pair of scissors, and sometimes the tool kicks back and has to be reset onto the area it just gripped. Many times, the straight blade produces more force that is focused at the base as well. Curved blades usually have four points of contact for cutting and usually pull in the material they are cutting toward the bottom of the blades, where the greatest force is applied (photo 4).
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Look at some of the new cutters on the market. Some have a U-shaped blades, which pull whatever is in between the blades into the base of the blades to maximize cutting force. However, the curved-blade design will allow the blade tips to “grip” whatever they cut. This helps to hold the tool as it works. The straight blade works much the same way, but the material is gripped by the inside of the blades as low as the cut will allow. The U-shaped design does not, and you need to change your technique when cutting lighter-weight materials. Hardened materials usually do not need this type of grip.
With our “magic” cutter in our hands, how and what do we need to cut? You need to focus on all the above tool evolutions, so we will consider each evolution and look at methods for cutting successfully.
ROOF EVOLUTIONS
Let’s start with roof evolutions, such as roof post cuts or relief cuts for roof displacement. The big issues, as with all tool evolutions, are the vehicle’s materials and construction. Some of the ultra-high-strength roof reinforcements include boron steel, the same material as the door crash bar/beam. Such materials make the cutter twist and bend as the material is weakened. Take a look at these cuts-the tool will take the path of least resistance, so you need to anticipate where the cutter will go and maybe flip the tool over. Many times, this method helps keep the cutter in line with the cut you want to make and even makes the cut easier to accomplish. Make sure the blades go completely around the post and 90 degrees to the component being cut.
Don’t forget to strip interior trim to locate the side curtain airbag gas generators; removing this trim strip also allows you to look at the post, see reinforcement locations, and cut the post at its weakest point.
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Make sure there is a hard protection barrier between the tool and the victim and the interior rescuer. This is especially important today: Cutting hardened materials sometimes creates small hardened debris that flies about (photo 5).
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In making the cut, ensure that the tool closes completely and makes the cut fully. Sometimes, we have to wait for the second stage of the power unit to kick in to make the cut. Also, allow for compression of the foam reinforcement in the post to enable the cut. This means you need to visualize your cut, listen to the tool and its action as it cuts, and inspect the cut when the tool is removed to ensure it is complete (photo 6). For safety, always return the cutter blades to the “tips touching” position whenever a cut is complete. Remember to check the “B” post for the adjustable seat belt bracket; you don’t want to cut through it, as it, too, is made of hardened material. Also, remember the vehicle’s structure also has crash “energy” stored in it at times. When you sever the roof post, sometimes it will snap or pop as this energy is released.
DOORS AND SIDES
Moving on to the doors and sides of the vehicle, let’s revisit the door pop. When popping doors today, more often than not, the door materials shred, tear, and rip apart, requiring us to try to spread another way or cut off the door.
Why does this happen? The lightweight door materials and high-strength latches and hinges are “coupled” by the door crash beam. The whole door assembly is tied together more tightly than before because of vehicle construction and design and its inherent ability to transfer crash energy throughout the vehicle structure. This makes door pops problematic.
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Since today’s cutters can make short work of hinges and latches, why not just cut them in the first place? Cutting these items to remove the door creates much less stress and strain on the vehicle, thus easing stress on the victim and the tool operator. The evolution actually goes faster and more smoothly than a traditional door pop, making it safer for all as well (photo 7).
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The key to this evolution is to “visualize what you seek”-i.e., observe the hinge and the latch. Ensure the cutter blades get completely around the hinge or latch. Don’t place the tips of the cutter on the hinge; this will cause the tool to be “tip loaded” and damage the blades. Make space between the door and the vehicle body to get the blades in and around the objects to be cut (photo 8).
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Watch tool reaction here as well, since many times the material being cut is square or rectangular, which will cause the cutter to “swing” or torque quickly; watch it closely. Also ensure that hard protection is in place between the tool work and the victim and interior rescuer. Now, as with roof-post cuts, as you find wires in your path, cut them with a hand cutter such as medic shears or battery cable cutters. Why? More vehicles are equipped with side-impact airbags in doors and side curtains in roof edges, which are impacted by static electricity as well as pressure and shock. As with door pops, side removals call for using cutter relief cuts into the “B” post. These areas are usually well reinforced, so cutting can be difficult. Displace trim at the base and top of the B post to check for seat belt pretensioners, side curtain cylinders, and the adjustable seat belt bracket (photo 9).
DASH DISPLACEMENT
In dash displacement and strategic cutting, we are also dealing with newer, stronger alloys in many places. Again, we return to vehicle construction and the role it plays in energy absorption and those new hardened materials and dash reinforcement. You need to make appropriate relief cuts to raise the dash and also have to look deeper and strategically weaken the vehicle’s structural integrity so you can displace the dash more effectively.
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First, look at that strategic cutting. You want to make a vertical cut into the vehicle’s “crumple” or “crush” zone. This isolates the dash area from the rest the vehicle, especially when making the relief cuts to displace the dash. You need a cutter that can open wide enough and has enough power to make a deep cut into the crush zone and sever it completely. Often, you will have to cut and displace or spread and displace the fender to make that strategic cut (photo 10).
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In dash displacement, you need to make a relief cut to roll the dash or, preferably, lift the dash. One of the areas to “cheat” for these cuts is the hole through which the wiring passes through to the door. Just pop that rubber boot out of the way, and make a cut through both sides of the knockout hole area (photo 11). To displace the dash, remove the roof or cut a six-inch piece out of the “A” post to allow for dash travel as it is displaced.
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As already discussed, you need to ensure that your cuts are complete (ensure that the blades completely cross each other) and have hard protection in place between the tool work and the victim and interior rescuer. The dash lift works so well today because the dash reinforcement bar holds the dash and firewall integrity well, which allows you to apply force upward to make that bar into simple mechanical advantage (photos 12).
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As vehicle design progresses, cutting is used more often in extrication. Although it is important to use the spreader appropriately, the cutter is fast becoming the all-important tool for expediting evolutions and making them safer. Current vehicle construction and the materials used significantly impact first responders; you need to understand how your tools will interact with these factors and how evolutions will be affected. Observe better the materials you are cutting and how your tools react, and always remember to properly protect your victims and yourself. Spend more time practicing techniques for cutting hardened materials and observing tool reaction. When using cutting tools in conjunction with other tools on-scene, stress that 10- to 15-minute scene time, so you can ensure a better, more positive victim outcome and make the appropriate space needed. ■
■ DAVE DALRYMPLE is a career EMS provider for Robert Wood Johnson University Hospital/St. Peter’s University Hospital Emergency Services in New Brunswick, New Jersey. He is also a firefighter/EMT/rescue technician and former rescue services captain of the Clinton (NJ) Rescue Squad. Dalrymple is the education chair of the Transportation Emergency Rescue Committee-US and serves on the Expert Technical Advisory Board of the International Emergency Technical Rescue Institute as the road traffic accident advisor.
