Heavyweight approach for truck RTCs
Published: 01 September, 2008
As the pressure on Europe’s infrastructure increases so do the number of RTCs that involve HGVs. Three experts provide some recommendations – including equipment tips – for these supersize incidents.
According to Brendon Morris, technical rescue consultant for Holmatro Rescue in the Netherlands, many rescuers make the mistake of thinking that a heavy goods vehicle RTC is similar to a passenger car collision, but on a larger scale. “The reality is that anything that has been designed to carry a heavy load from the ground up – buses and trucks – is built very differently.”
Modern light motor vehicles are built according to the monocoque construction principle (also called unibody construction), where the whole vehicle is made from one frame. Heavy goods vehicles, on the other hand, are built on a rigid steel chassis on which all other parts of the vehicle are based, including the cabin.
There are many stabilisation issues that have to be taken into account during the approach to a heavy goods vehicle RTC. The biggest challenge, says Morris, relates to the fact that all the weight of an HGV is placed above the suspension. This means that the concept of simply placing wedge blocks under the vehicle – as you would do with a light motor vehicle – is not going to work with a truck or a bus, because there are greater distances between the ground and the body. And while on a car there are few suspension links, on HGVs there are many, making isolating them a complex operation.
Morris considers the floating cabins as another issue that requires attention. To make the ride more comfortable for the occupants truck builders have implemented flexibility between the cabin and the chassis – another factor that needs to be controlled during the stabilisation process.
In many instances stabilisation is achieved by strapping the cabin down to the chassis and stabilising from the ground upwards with suitable shoring.
Morris believes that platforms are a good way of tackling height issues during heavy goods vehicle RTCs. However they do bring their own set of challenges. “The people who are using these platforms need to be very clear about what is appropriate. When you have a group working at height next to a truck, every team member has to be singing off the same hymn sheet in terms of equipment placement and how many people are using it at one time.”
It is ironic, thinks Morris, that the gap in the size of cutting and spreading equipment used for HGV and passenger car extrication is narrowing. And the cause is the monocoque construction used in passenger cars. “There is still a need for slightly heavier capacity equipment for trucks in most cases. However, with the massive construction advances in the light motor vehicle industry, there is now often a requirement for heavy cutting equipment in conventional RTCs. The parts you want to cut on an HGV are usually stronger than in a car, but the increase in material strength of high-end passenger cars means the differences between the equipment required for the two types of vehicles are definitely getting smaller.”
Specifically in bus extrication, having very heavy-duty cutters is not always necessary, says Morris, although the rescuer may need them for initial entry. Most of the entrapment here is seen between the seats and internal structures, so therefore battery powered combi-tool technology and portable rescue tools are usually far more useful, because the rescuer is working inside the bus.
Morris has spotted another trend that has far reaching consequences for the type of rescue equipment chosen for collisions between trucks and passenger vehicles. “Particularly in continental Europe we are noticing that light motor vehicles, when they are involved in collisions with trucks, are moving further underneath the heavy goods vehicles.”
The main reason for this is that light motor vehicles are built to absorb energy in order to decrease the amount of deceleration that is experienced by the occupant of the car when it crashes. So, while the occupants may survive due to the car’s new construction technology, they are then stuck under the truck. This has serious implications for the rescue operation because there is a risk that the truck will fall onto the car whilst cutting is taking place.
In many cases the truck may need to be tilted, and Holmatro has developed special integrated hydraulics into its shoring system for this purpose. “The rescue shoring system with integrated hydraulic lifting capacity is fairly standard. When rescuers decide that the truck needs to be tilted to get better access to the victims, hand pumps can be connected to the hydraulic shoring equipment to achieve a tilt, using the stable shored platform that was set up during an earlier stage of the rescue.”
One last important consideration during the extrication process is the nature of the load. Obviously, Morris recommends taking the appropriate HazMat measures if a load is considered hazardous. “However, if the load is liquid and there is a leak, then the vehicle will gradually get lighter so any stabilisation that has been put in place needs to be able to capture the load as it evolves – not just how the load was perceived at the exact moment that the rescuers arrived.”
