Extrication dilemma: Door hinge or latch attack?
While no one technique is suited for every extrication situation, one method is far better most of the time
One of the essentials to gaining access at a motor vehicle collision is door removals. Seconds really can matter. But do we consider our approaches with that degree of scrutiny?
Too often we do not. We become comfortable with a specific approach and get stuck. We don’t evolve with new automotive construction and we get stuck with archaic techniques and tools.
We can sometimes overlook how many ways there are to perform extrication sequences. We can also be presumptuous and too comfortable with our techniques of choice and not question if they are the most efficient ways to moving metal.
It is imperative to continuously analyze our techniques and equipment and expand our knowledge base through training, listening, learning and constant field applications.
I was recently at private extrication consortium with some of the world’s leaders in extrication training. Jason Defosse from Code 4 in Canada and I were having an in-depth conversation about various techniques and approaches to gain side access into a vehicle.
Defosse said he prefers to attack the hinges over the latches as primary objectives. I have always been less convicted in my own approach between hinges or latch and pin assemblies when spreading doors.
However, as we were scrolling through volumes of extrication pictures and considering the techniques we had been a part of during that day’s extrication sequences, I became increasingly convinced of his perspective.
When considering the typical position of victims and the construction of modern door assemblies, there are some key points to illustrate the variables between hinge attacks and latch/pin attacks.
If the driver is pinned and we want to force the driver’s-side door, first consider the driver’s body position. In most cases, the driver’s most vital body parts are all in close proximity to the B post and the door’s latch and pin assembly. The door’s hinges are located on the A pillar and provide an attack point farther away from the victim.
Now we can consider the vehicle design. Doors are composed of an inner and outer skin with a reinforced skeleton sandwiched in between. The two skins are connected by an overlapping flange around the perimeter of the outer skin that is simply glued with automotive epoxy to the inner skin.
When attempting to spread by placing the tips directly on the edges of these two skins, the two skins or panels almost immediate separate. This reduces the door’s structural integrity and often results in a spreading action that simply peels off the outer panel and does not carry the inner panel with it.
So, whether we are attacking the hinge side or the pin/latch side of the door, we have to gain access to the inner skin and the interior pillars or posts. This is most readily accomplished by expanding the window opening vertically with a hydraulic spreader.
If the attack point is the hinge side, the window opening is narrower because of the angled A post. This will enhance the spreading distance, or the push, that can be achieved by pushing off the angled A post with the spreader.
In many instances, the initial window spread can separate the top hinge. This movement also opens a gap and access point into the front fender to quickly separate the fender panel with a high-side lateral spread.
By starting high with the spread, you can usually separate all of the connecting bolts along the top of the fender rail. Then place the spreader low to separate the low-side connecting bolts on the fender.
This exposes the inner construction of the fender rail and strut tower and the lower door hinge. The lower door hinge can now be quickly spread apart.
Once these steps are complete, we are left with a door attached to the B post with a single connection point – the latch/pin assembly. Defosse prefers to squeeze the spreaders onto the hinge side of the door and applies steady leverage to the door, swinging it outward and essentially turning the latch/pin into a hinge.
This applies significant mechanical advantage through leverage to that connection and will either result in separating the connection or gapping it significantly. If the connection doesn’t separate, walk the door back in a little, and then spread or cut the latch and pin assembly.
There are some challenges often encountered on newer vehicles when attacking the latch/pin assembly first.
Performing the window spread toward the rear of the driver’s door places the tips of the spreader in very close proximity to the victim’s vital areas. This can be done, but it increases risk and requires more time and caution.
Additionally, we can cannot generate the same distance of expansion because the push point (the interior roof rail) and the expansion point (the interior door skin) are farther apart than the angled A post. The result is less spread, usually not enough to fully pop or separate the latch/pin assembly.
So, the next move is to relocate the spreaders to a point between the high B post and the window rail. This provides a structural push of inside to inside, which is what we are always looking for.
However, where the window rail meets the two door skins is a weaker construction point. This area is often a narrower expanse of sheet metal than the angular front window rail and its marriage into the door panels.
This often translate into a shearing effect right at the junction between the rail and the door panels at the rear. This is particularly true if the spread is not gradual and progressively done with incremental spreads working closer and closer to the latch/pin assembly.
Once we do make it to the latch/pin assembly, we have significantly worked and weakened all of the metal around the latch/pin and too many times experience shearing around the inner door skin. To sum it up, the latch/pin approach may take many more movements, time and effort to achieve the goal than the hinge approach.
We can never perform extrications with one “end all, be all” technique or approach. There are definitely occasions where a latch/pin side attack will be appropriate.
But for the vast majority of door removals, the hinge side certainly requires less movements, exposes more essential areas of the vehicle and offers increased reliability for response to the technique.
Now that we have discussed the pros and cons of which end of the door to attack, we can move onto the next big debate. Do we cut the hinges or spread the hinges?
The first piece of this puzzle should be the big picture and tool maximization. If one of the tools in question can be performing a vital role in another area of the vehicle, then go after the hinges with what you have.
I am a huge believer in keeping multiple tools working simultaneously when possible.
For example, if the rear door needs forced as well, the initial objective may be for the spreader to expand the front window and blow the top hinge and gap the bottom hinge. It can then relocate to the rear door to cut the bottom hinge and initiate relief cuts on the A pillar and fender rail for a dash displacement.
That is just one example where the collective objectives would drive various tool and technique choices. If the cutter was going to be used to eliminate the hinge connections, then cutter capability and orientation is the next piece to assess.
Not every cutter on the market can cut every hinge on the road, especially if it is placed in a horizontal orientation or parallel to the ground. This can be the most difficult position for cutters to eliminate hinges.
If a hinge is ¼ inch thick and 2 inches tall, then when we attack it horizontally we are attempting to cut a 2-inch thick piece of stock with only a ¼ inch of the blades.
If we orient the tool vertically so it is coming straight down onto the hinge, we are now attempting to cut a ¼-inch thick piece of stock with 2 inches of blade. This approach maximizes the capabilities of the cutter and will radically increase the potential for the cut to be a success.
In my experience, a hinge often spreads faster than it cuts. This is specifically evident when the looking at the overall movements and time for tool changes when the spreader is already in position to spread the top hinge and gap the bottom hinge. Why not just keep spreading?
Don’t take our word for it. Go test it.
Remember that is essential to know the limitations of your tool cache. Find as many techniques and approaches as possible to be effective problem solvers.
The rescuer who can think with clarity and understanding and effectively perform techniques with adequate tools will win every time. Be a thinker.
Stay safe and train hard.