Chocking and Blocking
Because the wheels of a rig or trailer were not chocked and blocked, workers are disabled or fatally injured every year.
An essential part of a safe working environment is the proper design and maintenance of equipment, including
chocks and blocks. Many roll-away accidents are caused by a failure to chock the wheels. In some instances,
drivers are crushed by their own rigs, while in others lift operators are disabled because the trailer rolls from the
dock, dumping the lift on them. A unit at a dock should always be chocked. Lift operators should never enter a
trailer without first verifying that it has been chocked.
The purpose of the chock is to pin the wheels and hold them stationary. Therefore, the rearmost axle on a
tandem-axle trailer should be chocked. The force of the lift entering the trailer exerts a downward force, helping to
pin the wheels more than if the front axle is chocked. If the front axle is chocked, sometimes the forward motion of a
lift entering a trailer can move the chock forward, allowing the trailer to pick up momentum and jump the chock.
Platform parking areas should be equipped with wheel chocks, which can keep vehicles from moving while being
loaded or unloaded, especially if forklift trucks are used. Equally important is blocking freight inside the trailer; this
lessens the chance of a load shift, which can cause a trailer to turn over or damage other cargo.
The principle used in chocking, securing to prevent movement, is also used in blocking. To prevent any movement,
it is necessary to block all four sides and to block each item separately.
Cargo doesn’t necessarily have to be round (such as reels or machinery on wheels) to move. How about a skid that
rests on runners? Better toe it with nails to be sure.
The type of blocking material used is also important. Make certain that nails or spikes are long enough and the
lumber is thick enough to prevent the cargo from shifting. Use only sound blocking materials, and never use other
freight as a block, unless you are willing to pay a claim on the block.
True or False Points:
1 Chocking wheels and loads keep them from moving and causing injuries. – T
2 The use of freight to chock wheels is OK. – F
3 Flat cargo can shift as well as round cargo. – F
4 The purpose of chocks is to pin wheels so that they move in only one direction. – F
5 Roll-away accidents are caused by not setting brakes not by chocking. – F
* A Safe Job Can Be “Chocked” Up to Safe Habits *