This month, we focus our discussion in the area of heavy commercial vehicle extrications with a focus on vehicle under-ride incidents and the type of resources that will be needed to mitigate the incident. As we noted previously, dealing with these large road haulers will tax the capabilities of even the best rescue companies; it is of paramount concern that rescuers respect the potential for considerable long-term operations and multiple action areas within the inner scene circle.
First, upon receiving a dispatch to an extrication that involves a large commercial vehicle, be sure that the right resources are responding as soon as possible. Considering the potential for multiple injuries and significant entrapment issues, it is wise to get the troops on the road immediately; they can always be sent back if they are not needed. Be sure to make contact with a response-capable heavy wrecker company; in the event of an under-ride or rollover incident involving passenger vehicles and commercial vehicles, a heavy duty wrecker with a rotating boom assembly would prove to be advantageous on the scene (photo 1). Coordinate these resources with local law enforcement, as many police departments have these resources categorized and “on-standby” to respond to major roadways in your response area. Be sure to notify them immediately upon arrival if you think that their services might be needed.
There will be significant potential for an increased hazardous material release. Most times, when dealing with passenger vehicle extrications, the fuel system will remain somewhat intact; there may be a leaking fuel line, but for the most part, it will be able to be controlled with minimal additional resources. Commercial trucks, however, pose a larger risk. Notwithstanding the materials that are being transported, most large tractor trailers can carry upwards of 300 gallons of fuel in dual saddle tanks directly under the cab (photo 2). Not only is this a potential combustibility issue, but unless the material is contained or controlled, patient access may require your rescuers to work directly over the product when it is released onto the roadway. Furthermore, many trailers have fuel cells mounted at the bottom of the trailer for the refrigerator unit. Under-ride incidents involving the trailer can also result in a potential combustible atmosphere. Have the resources needed to handle this issue quickly so the extrication can be set into action.
Upon arrival, after scene safety has been secured, there is one critical question that has to be answered: Where is/are the victim(s)? The victim location will define what type of operation will be needed (Lift, move, swing, drag, etc…) and what additional resources are going to be required (photo 3). Secondly, stabilization needs will be difficult. Frame rails for commercial vehicles are much higher than what are found on passenger vehicles. Larger sized cribbing and raker struts may be needed, not only for an increase in weight support, but to provide for height gain in our crib stacks. Furthermore, when it comes to cribbing these vehicles, the cab of the truck will need additional cribbing from the frame rails to the underside of the cab. These vehicles not only have body-mount assemblies, but many of these are spring-loaded or pneumatically charged to adjust the ride for the operator. The cab “load” will also have to be directed to the ground through the frame rails as well.
Once we have identified the victim location and the plan to remove them, we need to consider the next point: Is there a need to displace or move the vehicle(s)? When we have to lift or move a vehicle (think under-ride or over-ride with a passenger car), we need to know the weight of what we will be moving. One quick way to get a rough idea of the potential weight of the vehicle involves counting the axles and adding the weight ratings together. A good rule of thumb for axle weight is: