A loading dock or loading bay is an area of a building where goods vehicles (usually road or rail) are loaded and unloaded. They are commonly found on commercial and industrial buildings, and warehouses in particular. Loading docks may be exterior, flush with the building envelope, or fully enclosed. They are part of a facility's service or utility infrastructure, typically providing direct access to staging areas, storage rooms, and freight elevators.[1]
In order to facilitate material handling, loading docks may be equipped with the following:
Warehouses that handle palletized freight use a dock leveler, so items can be easily loaded and unloaded using power moving equipment (e.g. a forklift). When a truck backs into such a loading dock, the bumpers on the loading dock and the bumpers on the trailer come into contact but may leave a gap; also, the warehouse floor and the trailer deck may not be horizontally aligned. In North America, the most common dock height is 48inches-52inchesin (-in), though heights of up to 55inches occur as well.[1] A dock leveler bridges the gap between a truck and a warehouse to safely accommodate a forklift.
Where it is not practical to install permanent concrete loading docks, or for temporary situations, then it is common to use a mobile version of the loading dock, often called a yard ramp.
There can be very serious accidents on loading bays. One example is trailer creep (also known as trailer walk, or dock walk), which occurs when the lateral and vertical forces exerted each time a forklift truck enters and exits the trailer cause the trailer to slowly move away from the dock, resulting in separation from the dock leveler. Factors that affect trailer creep are the weight and speed of the lift truck and load, the gradient of the ground the trailer is parked on, the condition of the suspension, tire air pressures, the type of transition being used (dock levelers, dock boards), and whether the trailer has been disconnected or if it is still connected to the tractor. Trailer creep is often prevented by a vehicle restraint system.
Separation of a vehicle from the loading dock also occurs when a driver prematurely pulls away while the truck is still being loaded/unloaded. This issue is usually caused through a driver not correctly observing traffic lighting signals on a loading bay which prohibit the movement of the trailer. It is also important to ensure that drivers are adequately trained on the safe system of work they are expected to follow.
In different parts of the world, a section of a public or private road may be allocated for loading goods or persons, at specific or at all times. There are parking signs and/or road markings to warn motorists of parking regulations. These areas are known as loading zones or loading bays in many jurisdictions. They are generally monitored by parking inspectors, and vehicles found to be violating the rules can be towed or fined.[2] [3]
There are many ways to prevent an accident at a loading dock. Different forms of safety preparation include dock lights, back-up lights, trailer restraints, wheel chocks, heavy duty rising roller barrier, safety gates and safety netting. There are many online courses for safety training, and it is very important to regularly audit equipment, making sure that it is correctly assembled and in good working order.
A loading dock leveler is a piece of equipment which is typically mounted to the exterior dock face or recessed into a pit at a loading dock. Commonly referred to as “bridging the gap”, a dock leveler allows for the movement of industrial vehicles (e.g. forklifts, pallet jacks) between a building and a transport vehicle. Because of the different heights and sizes of many freight and semi-trucks, a dock leveler is an all-encompassing fixed solution to fit varying transports, capacities and budgets.
Although there are many different types of dock levelers[4] many share common components:
A flexible, less-expensive alternative to a loading dock leveler is a dock plate or dock board. Often more portable and not fixed to a dock or transport vehicle, dock plates and dock boards and metal ramps which help bridge the gap between dock and truck. Dock plates are commonly made out of aluminum and suited for lighter loads, such as handcars or dollies. Dock boards are generally made out of steel and suited for heavier loads such as motorized equipment or electric pallet jacks.