When we talk about heavy vehicle rescue, most think about tractor trailers. We must also think about specialty trucks as they can present more of a problem at times, than the large and heavy semi-trucks.
Specialty trucks cover a lot of the trucks on the road and the ones we find in the cities and on the secondary roads. We know that most large trucks are found on the interstates and that is where most of the crashes are involving these vehicles. This only makes sense, as the speeds are higher and there are more traveling on these highways. We have to also consider that specialty trucks not only travel the interstates, but are intercity as well. Let us look at some of the specialty trucks and why they are different.
Any truck that has a special or unique design as to what it does makes it a specialty truck. A fire apparatus is a specialty truck as it is designed to either pump water, carry water, extend a ladder, carry a ladder platform or carry rescue equipment. Even though all of these are types of fire apparatus, they are considered specialty trucks. Luckily, these are not the trucks we have to be concerned about when it comes to crashes. Not to say fire trucks are never involved in crashes, unfortunately they are sometimes.
A lot of your specialty trucks are found in the construction trade. Concrete trucks, concrete pumping trucks, dump trucks, cranes, and well drilling trucks, are all found on the roads and used in construction work. Other specialty trucks include garbage trucks, recycling trucks, logging trucks, etc. Several of these trucks can present particular problems due to the nature of their construction.
Let’s look at the concrete truck. Concrete trucks carry from one to 14 yards of concrete. Now, considering that concrete weighs 4000 pounds a cubic yard, and we forego the actual truck weight, there can be an added weight from 4000 pounds up to 56,000 pounds if carrying 14 cubic yards. Depending on the size of the concrete truck, they can weigh an average of 26,000 pounds. The legal weight in North Carolina is 80,000 pounds, with an exception for the logging industry, which can go up to 90,000 pounds. This applies if the transport is within 150 miles of the point of origination. So going back to the concrete truck, we can be dealing with a tremendous amount of weight.
The other concern is that most of the truck’s weight will be in the drum, unless the truck is empty. The drum has to continuously turn to prevent the concrete from hardening before it is delivered. The drum turns on a pivot system and uses a chain drive and motor to achieve this. During a stabilization and extrication, the fact that the drum can turn may present a problem and will need to be addressed. If the drum is loaded and does not turn, within a short time, the concrete will begin to harden. This could also cause an issue at the wreck scene.
Concrete trucks are also made of heavy grade steel that may cause difficulty trying to cut with a hydraulic cutter. The cab construction is framed steel, covered with sheet metal. The front window is laminated safety glass and the side and rear windows are tempered safety glass. The rear window is usually set in a rubber gasket and easy to remove. There are several designs with these trucks, some are front discharge and some are rear discharge. The distance between the cab and the drum may vary from truck to truck. These designs also affect the center of gravity of the truck, which will become a concern when the truck is overturned.
As you can see, there are a lot of things to consider when dealing with large and heavy vehicles and we will continue to examine these factors in the next series of articles. As always, train hard to be the best you can be, the lives you save are never forgotten. On another note, I would like to wish everyone a safe and blessed New Year.