By Mike Smith
Published Tuesday, August 21, 2012
| From the October 2012 Issue of FireRescue
The hot topic in extrication over the last few years has been advanced steels, ultra-high-strength steels, boron steels—and how to cut them.
In order to meet the latest government crash requirements and to reduce weight to improve fuel economy, automakers have used advanced steels like boron to add strength to their body structure. Further, the makers of hydraulic tools have stepped up to the plate and designed tools that can cut and spread their way through the strongest body structure on the road today. The problem: The fire service is still recovering from the economic meltdown, so asking for funding to replace outdated extrication equipment is a tough sell. As such, many departments can’t afford to purchase the tools necessary to cut high-strength steels and, therefore, must rely on other tactics to get the job done.
The good news is there are methods that rescuers can use to optimize operations on late-model body structures that feature high-strength steels:
#1: Limit the amount the cutter blades are opened prior to starting a cut on a post. Take a moment to think back to extrication 101. What are the strengths and weaknesses of hydraulic cutters? The cutting force is measured at the notch, and the cutters are weakest when the blades are completely open. A common approach to cutting the B-post is to completely open the cutter blades to fit around the post with the patient in the driver seat. The cutter is placed perpendicular to the side of the vehicle. If the placement of the cutters on the B-post is parallel to the side of the vehicle, the tool operator is able to reduce the amount that the blades are open prior to cutting. The cut is started with the blades closer together, maximizing the strength of the tool. Note: The tool operator must ensure that the cutters don’t rotate into the passenger compartment toward the patient.
#2: Know the materials. Identifying the material in a vehicle on scene is nearly impossible without computer programs like Moditech’s Crash Recovery System. Automakers are using different steels like tailored blanks that allow the material thickness to vary throughout the part. If a tool stalls during a cut, simply moving the tool up or down an inch or two can allow the tool operator to find thinner material or a less reinforced part of the post.
#3: Understand proper tool position and the angle of the tool to the surface of the vehicle. Tool operators will commonly hold the cutters parallel to the ground. Consider how the B-post arches toward the center of the vehicle. Placing the tool at a 90-degree angle to the surface of the post allows the cutter to cut the smallest cross section of material. Think of a miter cut on a piece of wood—more surface area of wood is cut on a 45-degree cut compared to a 90-degree cut.
In Sum
Firefighters and rescuers are trained to always think beyond the current task. Extrication is no different. Whenever you start one technique, you should think of a Plan B as well. What would you do if your cutters stalled during a cut or if the high-pressure hose was cut? You and your crew should know and practice workaround techniques for advanced steels, especially if your extrication equipment has not been replaced over the last few years. Train for the unexpected because training is what people revert to when things go wrong and during stressful situations.
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A common approach to cutting the B-post is to completely open the cutter blades to fit around the post with the patient in the driver seat. Photo Mike Smith
If the placement of the cutters on the B-post is parallel to the side of the vehicle, the tool operator is able to reduce the amount that the blades are open prior to cutting. Photo Mike Smith
