(Courtesy: Jmadamy1 at flickr.com)
During the last few posts I have been discussing loading dock design. In the first article titled Loading Dock, I covered safety considerations and the layout and creation of the area known as the apron space. This is the space in front of the loading dock where trucks can maneuver safely for proper positioning in a dock.
In the second article titled Loading Dock – II, I described the various loading dock designs including Cantilever, Enclosed, Flush Loading, Open Loading, and Saw Tooth. I also covered how one would go about designing and constructing the dock approach and the proper incline-decline of the approach.
The third article, Loading Dock- III, covered how to determine the proper dock height and door sizes.
This article, the last in the series, will cover what you need to know about dock bumpers including their arrangement, height, and thickness.
Dock Bumper Arrangements
A combination of bumpers configured vertically and horizontally, will provide the most thorough protection. If an 8-foot wide bay door receives trucks straight on, then a 24-inch high bumper on either side and a standard 10-inch high bumper in the center will provide the best protection. This set up will accommodate a host of trailer heights without the risk of trailers approaching below the 10-inch bumper in the center of the opening. If you use a refrigerated dock, then extra length dock bumpers would provide adequate protection for the door seal and will help to control airflow from the base of the door when used along with a dock seal.
It is recommended that you use a combination of bumpers to assure the best protection. Bumpers are available in customizable widths, so achieving the proper size should not be an issue. Make certain that all the bumpers are correctly installed to prevent the need for any maintenance.
Bumpers commonly come in three depths –- 6-inch, 10-inch, and 12-inch. If you need to protect a higher area, then you can stack pads on top of each other. This set up will allow you to protect heights of 20-inches, 24-inches, and 36-inches.
If your dock features a lip protruding from a wall that is 10-inches in height or less, then a 6-inch bumper will suffice. It is recommended that you use 10-inch bumpers for docks that require trucks to come in at about equal heights or when standard size trucks are to be accommodated. The tallest single pad is 12-inches.
The thickness of the bumper depends on the slope of the dock approach or the obstructions coming out from the dock face. A typical bumper has a thickness of 4.5-feet and would be ideal for a dock that features a level approach and no obstacles around the doorway. The bumper should extend out from the wall a minimum of 4-inches to the top of the tallest trailer. Use bumpers with greater thickness if the dock approach slopes down toward the dock.
Attach a string to the floor of the dock and walk off 50-inches following the direction of the trailer’s approach to determine the slope. Use a line level to ascertain the line drop at 50-feet and divide the number by 600. This will give you the percentage of the slope. For every percent of slope figure 1-inch of additional thickness on a standard 4.5-foot bumper’s thickness. So, doing the math, a 5 percent slope will need a 10-inch bumper projection.