Article, photos by David Dalrymple
We all know that vehicle construction and materials are changing rapidly. Tool evolutions of all types are becoming more difficult and complex each year. Not only do we need to understand tools and their function, we also need to understand vehicle construction methodology. We need to think smart in order to work smart these days. We are faced with structural reinforcements that are not only more numerous but increasingly more difficult to sever, whether that means using power hydraulics, a reciprocating saw, or other options, including vehicles themselves. We expect to find these concerns in high-end vehicles, but this article will reinforce the fact these are present in all vehicles.
This past August, Police Officer Barry Daskal of the Port Authority of New York and New Jersey Emergency Services Unit (ESU) shared some photos of a motor vehicle collision (MVC) he had responded to. As he described it, at 1601 hours on July 21, 2007, ESU Truck 8 and John F. Kennedy Airport police personnel responded to an auto extrication incident involving a New York City bus and a Dodge minivan. After displacing the driver’s side door and cutting the top of the B post, personnel attempted to cut the bottom of the B post. Despite numerous attempts and various tools, the B post could not be cut. After the extrication was completed, it was determined that the B post contained a tubular steel reinforcement rod that was approximately 1/4 to 3/8ths of an inch thick. Though not uncommon, this type of reinforcement is rarely seen outside of high-end vehicles, and defied being cut by the rescue tools in their department. They eventually cut it with a rotary K12 type saw.
A short time after seeing the photos Officer Daskal shared, my own combination department responded to a MVC with extrication on the interstate involving a car and a 2006 Chrysler minivan. This incident involved a front-seat passenger in the minivan who was medically entrapped and the front door and B post required removal to disentangle the patient. The passenger door removal was facilitated easily enough, but as we started to cut the B post I remembered the incident Officer Daskal described and the pictures he sent. I directed the rescue tech to cut the post as high as possible and then the base of the post as low as possible. We pulled the interior trim from the B post, both at the top and base. The top of the B post was cut fairly easily, but the base was another issue. We were able to cut below the seat belt spool and pretensioners directly in line with the vehicle’s floor. It took four cuts to sever the base of the B post. A cut was made to the front and back of the base and then to the outside of the base of the post. This allowed us to fold the B post outward and down, but we still were unable to detach it from the floor. Another cut had to be made to sever the base of the B post, this time from the rear. After the patient was extricated, we took the B post back to our station to take a better look at it.
On closer examination, I saw this post also had a reinforcement much like the one in the photos Officer Daskal sent. We had not severed the reinforcement but instead severed the bracket it was welded to in the vehicle’s floor. We noted that the lower third of the pipe was filled with polyester foam fill. We then stripped the outside skin of the B post. The reinforcement pipe ran from the top of the B post to the base of the post. The adjustable seatbelt bracket appeared to have its mounting bolts placed into openings that had been “burnt” into the pipe by some sort of torch, perhaps a plasma cutter. We then decided to try and cut the post with a power hydraulic cutter. The cutter we used was a Holmatro 4050 NCT cutter from our special service unit. We placed the B post into a bench vice and proceeded to cut. We timed the operation to see how long, if at all, it took to sever the post. After approximately 27 seconds (23 of that on the pump’s second stage) the post was severed. However, the section of the post that was “free” struck the concrete wall 10 feet away, dug a ¼ hole into the concrete block, bouncing off and landing about 30 feet away. We also noticed the pipe itself created some small debris and fragments as it was severed.
We then looked at the severed section. From its reaction to being cut as well as its visual appearance, I believe the material to be either HSLA or boron steel, but the thickness was indeed substantial, close to 3/8″ thick. We then switched the B post in the vise to the severed section. The next test we decided to try was to cut it with a reciprocating saw. We used a Dewalt 36-volt saw with two different blades. The 1st one was a Lenox Lazer blade–14 TPI. The second was also a Lenox Lazer blade, but at 10 TPI. Each cut was timed to 45 seconds. By the end of 45 seconds, each blade area used was scorched and the teeth worn almost completely down. During each cut we noticed a large amount of sparks given off. Each saw blade cut barely cut into the pipe, at the most 1/16-inch deep. The next tool we tried was a pneumatic wizzer saw, again timing the cut for 45 seconds. This time, the tool was able to cut halfway through the pipe in the time allotted, also giving off a tremendous amount of sparks.
We were very surprised by the tenacious ability of this B post to fend off our tools. One of the things we will see in the near future is an increasing difficultly in severing or displacing vehicle components, and here is a prime example of that housed in an everyday, commonplace vehicle. Think of the number of minivans that move about in your respective response areas, and get ready to deal with stronger vehicle components–soon.
David 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 as the road traffic accident advisor on the Expert Technical Advisory Board of the International Emergency Technical Rescue Institute.