Benefits of Drive-Through Design

Drive-through loading docks provide cleanliness, safety, and efficiency.


Since finished paper products are typically designed to have words or images printed on them or to package another product, it is essential that they look—and are—clean. When food and beverage labels or packaging are being manufactured, cleanliness is more than best practice: it’s the law.

A good dock shelter creates an environmental barrier between the back end of the semi-trailer and the outside border of the dock opening.

Any paper products that will eventually store or come in contact with food or beverages must comply with Food Safety Modernization Act (FSMA) standards. This includes keeping the loading dock clean, which is quite a challenge considering that the repeated opening of dock doors during loading and unloading is a prime opportunity for contaminants like rain to enter. Additionally, the loading dock is notoriously dangerous for workers and can be highly inefficient in terms of energy use.

To address these challenges, an increasing number of paper mills are upgrading their loading dock areas with a new dock configuration: the “drive-through.”

Unwanted intruders like rain, snow, dust, and debris can easily make their way into a paper mill through open loading dock doors. Because of this, most facilities are good about keeping doors closed when a truck isn’t there to be loaded or unloaded. However, most dock stations still provide passageways for these contaminants to enter even when trucks are secured to them and ready for loading and unloading. When traditional trailers are docked and their swing-open doors are opened, 1- to 2-inch gaps often exist between the trailer and the edges of the dock opening. While that might seem insignificant at first glance, it equates to a 2.5-square-foot hole at just one dock opening.

Perhaps the worst gap of all exists at the top of the dock opening. Many loading dock workers are all-too-familiar with the “waterfall” that can form at the top of the trailer if the opening is not completely sealed with a proper header.
These gaps also compromise temperature and humidity control, which can further lead to damaged goods. If not immediately damaged by water intrusion, any surviving paper products are more susceptible to being crinkled or torn when damp. That can mean entire orders being lost.

Above: Vertical levelers store up and out of the way.

Considering the amount of energy it takes to run a paper mill, the 2.5-foot hole described is an unnecessary drain on resources. In fact, these gaps around trailers can translate into thousands of dollars flying out the door. Just one dock position can represent anywhere from US$600 to US$1,200 worth of lost energy in a year. Multiply this over multiple dock doors and the financial loss can be significant.
But the sides of the dock opening aren’t the only gaps in the building’s perimeter. There’s also the “fourth side” of the dock – the bottom end, where the leveler, trailer, and dock seal or shelter all meet. Depending on the size of the opening, that gap can result in another US$200 to US$900 of energy waste, annually.

Besides being regimented in keeping loading dock doors closed when trailers aren’t secured for loading/unloading, one of the best ways to keep detrimental contaminants like rain out—and conditioned air in—is to address the perimeter of the dock door.

This can be achieved with a loading dock seal or shelter, which creates an environmental barrier between the back end of the semi-trailer and the outside border of the dock opening.

An effective dock sealing system helps prevent weather-related product damage and contamination, protecting and securing the integrity of products as they move in and out of a facility during manufacturing, processing, and shipping.

Increasingly, managers of all types of manufacturing plants are realizing that drive-through dock configurations are the “gold standard” for environmental control and energy efficiency. Drive-through dock applications are designed with a recessed pit and vertical-storing levelers, which allows trailer doors (and security seals) to be opened inside the loading dock, eliminating exposure to outside precipitation.

Drive-through docks are better from a safety and efficiency standpoint as well, since neither the driver nor the dock employees need to go outside and open the back of the trailer before it fully backs in and is secured to the dock wall.

Vertical levelers also have maintenance advantages. Unlike pit-style levelers, vertical levelers store up and out of the way, making it easier to clean them and wash down the floor. Moreover, vertical levelers (when in the stored position) allow the dock door to close directly onto the pit floor for a more water-tight seal.

Recently, dock shelters have been developed specifically for drive-through applications to work in tandem with vertical levelers. Thanks to special design features, these shelters ensure tight sealing against trailer sides, across the full width of the trailer top and at the corners, without interfering with trailer doors being opened and closed after the trailer has been parked and secured at the dock. When paired with the appropriate under-leveler dock seal, a superior four-sided closure is created around the entire dock opening.

The newest restraints incorporate “shadow” hook technology, which provides an additional layer of safety.

Operational efficiency and employee safety can also be enhanced through automated dock control systems. Most loading dock operations at paper mills require workers to operate various pieces of loading dock equipment (including vehicle restraints, levelers and overhead doors) independently of each other. This can lead to various human errors that may damage product or, even worse, cause injuries. However, with today’s dock control systems, facilities can ensure the equipment on their dock can only be engaged through a safe sequence of operation.

For instance, the most advanced systems can be programmed with a green light interlock, which disables the use of the hydraulic leveler or overhead door until the vehicle restraint is safely engaged; an overhead door interlock, which requires overhead doors to be opened prior to leveler operation; or a stored leveler interlock, which ensures that the leveler is stored safely before the restraint can release the trailer. If a worker presses the control box button for an individual system element in the wrong sequence, it won’t work. This control box helps ensure that no safety procedures will be skipped.

Regardless of the interlocking system (if any), the first step in securing the trailer as part of a drive-through operation is engagement of the vehicle restraint. Rotating hook restraints that secure trailers by the rear impact guard (RIG) have become ubiquitous at North American loading docks. However, in response to the increased prevalence of intermodal cargo and a growing diversity of trailer configurations that have an obstructed RIG, the newest restraints incorporate “shadow” hook technology. This type of hook provides an additional pivot point capable of securing trailer chassis with obstructed RIGs. These automatically activated restraints can also be integrated into building management or security systems and are upgradeable to include additional audio and visual communication cues for increased safety at the loading dock.

Quality paper starts with a clean, dry operation. Even the loading dock, a traditionally damp and unclean place, can be made much cleaner with a systematic drive-through design. Vertical dock levelers, appropriate seals/shelters and the latest vehicle restraint can combine to reduce contamination and energy waste, help protect employees, and even enhance the integrity of the overall supply chain.

Walt Swietlik is director of customer relations and sales support for Rite-Hite, a world leader in the manufacture and sale of loading dock equipment, industrial doors, safety barriers and HVLS industrial fans.