(Courtesy: Ray Forster, Flickr.com)
In previous articles I have discussed the different elements of a loading dock design including safety, apron space, truck bays, and the various styles of docks and dock approaches.
In this article I will discuss dock height and door sizes.
It should be obvious that proper dock height is an essential part of a well-designed loading dock. It ensures a smooth transfer of products to and from delivery trucks.
Things to consider when designing the proper dock height of the loading dock area include:
· The type of trucks that will be utilizing the dock.
· The grade capability of the material handling equipment on the dock.
· The dock leveler and board length that will accommodate the height differences that occur between truck and dock and truck and trailer “float” when items are unloaded or loaded onto a truck.
Most loading docks feature a height between 48-inches and 52-inches. The exact height you select should be based on the height of the various truck styles that pull into the dock. Calculate the average truck bed height and if the difference in dock height for the trucks is too great, consider using wheel risers and other options to ensure that all trucks that use your loading dock are properly accommodated.
Keep in mind that the maximum grade capability of a pallet jack is 3 percent, maximum grade capability of an electric pallet jack is 7 percent; maximum grade for an electric lift truck is 10 percent, and the maximum grade for a gasoline forklift is 15 percent. Go for the least incline/decline approach for the loading and unloading of vehicles to assure a longer life for the material handling equipment and dock leveler.
The proper door width and height is just as important as the proper dock height for the same reasons. The maximum legal width of a truck is 8-feet, 6-inches. So the width of your door should be able to accommodate that length.
There are three specific heights of a loading dock door –- 8-feet, 9-feet, and 10-feet. The 8-feet height will accommodate several high pallet uses, but does not accommodate for the maximum height of a trailer. The 9-feet height accommodates the maximum height of a trailer. The 10-feet height will accommodate the maximum height of a trailer, but it may be difficult to achieve full access to the back of the truck. To assure access to the back of the truck in the design of the dock, subtract the dock height from the maximum trailer height, and then round to the next foot. For example, subtract the 4-feet dock height from the 13-feet, 6-inch height of the maximum trailer height. That gives you 9-feet, 6-inches. So in this case consider a 10-feet high door so that you get full access to the back of the truck.
There are 12 styles of trucks and each feature their own bed height ranges.
Type of Truck Truck Bed Height Total Range
Double Axle Semi 45-inches – 55-inches
City Delivery 45-inches – 48-inches
Container 55-inches – 62-inches
Flatbed 47-inches – 62-inches
Furniture Van 23-inches – 36-inches
High Cube Van 35-inches – 43-inches
Low Boys 19-inches – 25-inches
Panel Truck 19-inches – 25-inches
Reefer 50-inches – 60-inches
Stake Truck 42-inches – 48-inches
Step Van 19-inches – 30-inches
Straight Semi 48-inches – 52-inches
Next Time: Dock Bumper Issues