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.
Operational Considerations
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:
Steering axles with thin profile tires = 12,000 pounds/axle weight rating
Steering axles with wide profile (flotation) tires = 25,000 pounds/axle weight rating
Drive axles on tractor/truck = 20,000 pounds/axle weight rating
Tag axles/trailer axles = 15,000 pounds/axle weight rating (Note: this is an averaged assumption; some may be rated for more, but it will get you started.)
Taking the above numbers into consideration, we can total the Gross Vehicle Weight Rating (GVWR) for a vehicle. For example, consider a twin-drive axle dump truck, equipped with a tag axle and wide profile tires on the steering axle. Based on the estimations above, the potential capacity of that truck and contents can weigh around 80,000 pounds (photo 4). What do you have in your resource caches that can lift/move/haul/hold these loads? Finding an answer to this question at the scene is not a good plan. Don’t forget about the properties of the cargo; solids, liquids and gases all react differently when they are displaced, and some of them can provide enough inertia to cause vehicle displacement in an adverse direction. Some container trucks must be off-loaded prior to lifting; be sure to check with the experts before trying something that may end in disaster.
Displacement and separation may be as simple as wrapping the vehicles’ suspension systems with chains and load/ratchet binders. Many rescue companies have opted to carry large flat load straps on their rigs. These straps can be deployed much easier than grade 80 chains can, and are not as bulky to work with. These straps will have hooks and connection points on them to be utilized on frame rails, rims, suspension parts, etc. (photos 5 and 6). Wrapping the suspension systems tight will result in 5 to 6 inches of displacement in passenger vehicles, and up to 12 inches when lifting larger vehicles off of passenger cars. When the suspensions are under compression, it may provide an adequate amount of displacement to separate the vehicles so that disentanglement procedures can begin. If not, then the larger vehicle will most likely need to be lifted or displaced from the smaller vehicle. If this is the case, you will need cribbing and associated strut supporting equipment that is strong enough to handle the working load limit of the vehicle. A combination of resources may have to be utilized in order to lift the larger vehicle. For example, a heavy duty wrecker may provide the strength to raise the larger vehicle high enough to separate the vehicles, but will benefit from cribbing and support from the underside of the vehicle, if possible (photo 7).
Once the lift is done, it may be necessary to separate the vehicle(s) and begin the extrication. This may require dragging the passenger vehicle back from underneath the commercial vehicle. There will be numerous entanglements between the two vehicles, in the form of rear ICC bars, frame rails, body Beams and supports, and electrical wiring and pneumatic tubing. It might be necessary to cut the vehicles apart after the lift is completed (photos 8 and 9). While I understand that the “move the victim and the vehicle” approach is a bit controversial, and this may raise an eyebrow (or considerably more) on a few rescuers, let’s consider two very critical points to this argument:
1. It is not recommended to be working underneath any suspended load. If your resources on-scene can not only lift, but stabilize the load in such a way that your crews will be protected while they work on the smaller vehicle, then go right ahead and begin patient care. However, it has been my experience that is not possible very often (if at all).
2. If your rescuers cannot access the patient, then they cannot provide patient care. Having discussed this position with a few trauma physicians, most of them echo a common fact about patient care; they can fix a lot of things on a person, but they can’t fix dead. That not only stands to reason for the patient, but for the rescuer as well.
Keep this in mind: it may not be necessary to move the vehicle the patient is in. For example, it may just be a question of uprighting a commercial vehicle that has come to rest on top of a car. Once that occurs, patient care can happen immediately. Do not operate with “functional fixation”; these incidents will require some detailed analysis and thought to come up with a solution, so be flexible.
Conclusion
Extrication scenes can be stressful, fast-paced, and tedious at the same time. Throw a large commercial vehicle into the fray and the scene now has added potential kinetic energy hazards, hazardous material control, lifting and moving issues, and considerable reactive forces at work during the incident. Make it a point to include a commercial vehicle into your next extrication training session; even if your rescuers do not cut or spread it, just working on moving it will require some considerable effort. Don’t let your next lesson in this field be in the middle of the highway.
Until next time, stay focused and stay safe.
MICHAEL P. DALEY is a lieutenant and training officer with the Monroe Township, NJ, Fire District No. 3, and is an instructor with the Middlesex County Fire Academy, where he is responsible for rescue training curriculum development. Mike has an extensive background in fire service operations and holds degrees in business management and public safety administration. He was named a Master Fire Instructor from the International Society of Fire Service Instructors. Mike serves as a rescue officer with the New Jersey Urban Search and Rescue Task Force 1 and is a managing member for Fire Service Performance Concepts, a consultant group that provides assistance and support to fire departments with their training programs and course development. You can reach Michael by e-mail at:[email protected].
