Cribbing / Stabilization

Cribbing is an aspect of Auto Extrication that is too often neglected. But it must be understood that a vehicle involved in a motor vehicle accident must be cribbed to prevent movement and subsequent injury to those inside.

Every accident scene must be evaluated to decide how much cribbing will be needed. If no extrication is required then only wheel chocks will be required, to prevent unexpected horizontal movement of the vehicle. If there are patients with severe injuries and if rescuers will be required to enter the vehicle, then more elaborate stabilization will be required.

Rescuers who enter a vehicle at an accident scene will certainly cause movement to the vehicle and possibly further injury to occupants if proper stabilization is not completed. Given all the possible tasks that rescuers are required to perform, and respecting the restraints of the "golden hour", little time can be afforded to stabilization. Therefore rescuers need efficient tools and techniques to accomplish this task.

Basic principles:

• It is generally agreed that soft wood cribbing is preferable since it is lighter, allows metal to grip into it, and is cheaper to purchase.
• Cribbing is normally supplied in 18" lengths.
• It used to be that 2x4's and 4x4's plus 4x4" wedges were the most common sizes, but with the popularity of Vans, Pickups and SUV's, with their increased road clearance, it is recommended that larger cribbing be available as well.
• Mark your vehicle # on the end of your cribbing.
• Two new sizes that are very useful are 6x8's and also 6x6" wedges. This allows fewer pieces to be used to accomplish the task. Cribbing equipped with carrying ropes as shown in the photo can easily be carried from the rescue vehicle to the scene. The 6x8x18" blocks allow a single piece of cribbing to fill two different sizes of spaces (6" or 8").

• Cribbing can be carried in boxes; however, more cribbing will fit if carried loose in a truck box compartment.
• When making the 6x6" wedges, be sure that they are cut from a 6x6" block leaving 1" thickness at the pointed ends. This makes the best angle for the wedge and makes the pointed edge less breakable.
• It should be noted that one 6x8" block with a 6x6" wedge is at least as high as the traditional "step chocks," and has a better chance of making contact with the vehicle frame.

It is standard practice to stabilize a vehicle from the same lift points that mechanics use in servicing vehicles, namely under the "A" and "C" posts.

If a rescuer is assigned the task of stabilizing one side of a vehicle, a quick look at the points to be filled with cribbing should give an idea of how much cribbing will be needed and then the appropriate amount can be brought from the rescue vehicle.

Many rescue scenes have been littered with excess cribbing (and tools) causing trip hazards. Every rescuer should keep an eye out for such hazards.

Once the cribbing has been placed firmly in place, it may be advisable to remove the air from the vehicle's tires. It is wise to recheck the cribbing from time to time as rescuers enter the vehicle or when metal etc. is removed, changing the weight and balance of the vehicle.

To this point we have referred to vehicles on their wheels.

Vehicles on their sides present extra challenges.

Again each accident will require different tactics.

Firstly, the tip hazards must be evaluated and primary stabilization may be in the form of wedges placed relative to the "A" and "C" posts, making sure that, in doing so, rescuers do not place themselves in a hazardous position. Then whatever form of longer bracing that is available should be placed to form a 60 degree angle with the ground. Remember that most vehicles have the engine in the front and therefore the greatest proportion of the weight is ahead of the "A" post.

If the cribbing is to be placed on soft ground, then larger pieces such as plywood protection boards or back boards could be placed first to spread the load, thereby preventing the cribbing from sinking in.

Vehicles on their roofs present unique challenges. Remember that the weight of the engine will probably force the front end to the ground, but the front end should still be wedged and stabilized. Again, secondary wedges can be placed at the strength points of the "A" or "C" posts or if necessary under the trunk area, but these should be placed to the sides so as not to impede rescue operations through the rear deck.

Be sure to advise scene command as soon as the vehicle is completely stabilized, so that the order can be given for the vehicle to be entered.

The amount of cribbing carried on a rescue vehicle may vary due to space limitations. The following is a reasonable standard.

4- 2"x4"x18"

8- 4"x4"x18"

8- 4"x4"x18" wedges

8- 6"x8"x18"

8- 6"x6"x 18" wedges

2- 4"x4"x8'

4- 4"x4"x6'

4- 4"x4"x4'

Great creativity has been seen in pursuit of the goal of stopping a vehicle from moving horizontally. One item has been invented for the purpose: it is called a wheel chock. Nothing else works as well for the purpose of vehicle rescue. These need not be the expensive steel or aluminum chocks. Many stores offer plastic chocks which are very economical and are adequate for most rescues.

Wheel chocks should usually be the first tools deployed. A standard load of 4 such wheel chocks is recommended.

Any questions or concerns should be directed to Alex MacDonald at amacd@extrication.ca