Sealing the Loading Dock Delivers Energy Savings
By Steve Kalbfleisch
In Canada, the idea of saving energy is ingrained in our culture because of the cost of protecting ourselves from the elements. So, when management decides to put its facility on an energy diet, its attention generally has been aimed at high-profile, renewable-energy equipment such as solar panels and fuel cells, or “low-hanging fruit” devices, such as lighting sensors and waterless toilets. Yet some of the solutions with the biggest energy savings potential offering the fastest payback can be found on the loading dock.
September 9, 2011 By Steve Kalbfleisch
The Material Handling Industry of America (MHIA) recently released the results of a study entitled “Sustainability in Warehousing, Distribution and Manufacturing”, which indicates that sustainability is a significant and growing trend in supply chains. According to the report, 48% of the respondents have sustainability initiatives underway, while 88% say that sustainability will be of even greater importance within the next 18 months.
Many of the survey participants associated equipment such as automatic identification technologies, controls, lift trucks, and even totes as playing a major role in sustainability, yet only 7% identified dock equipment as a potential energy saver. However, few areas in a plant or distribution facility offer as many opportunities for controlling energy loss as the loading dock—especially the potentially large hole at the dock doorway.
Efficiencies and improvements at the loading dock can be made relatively quickly, offering prime opportunities to combat energy loss.
In many busy facilities, the dock door typically has gaps because it has been badly damaged by a forklift. Each 8 x 10-ft dock doorway is an escape hatch for conditioned air, and a means for outside weather to invade the building. The cumulative effect of gaps at numerous doors can equate to an alarming amount of energy loss.
Damaged doors and ineffective and difficult to close. Picture a 5-ton vehicle weaving through an obstacle course in a confined space under a tight schedule. That is what a forklift does, and that is why damage occurs frequently to loading dock equipment—especially to dock doors.
For years, loading dock doors have been designed like garage doors. A forklift collision impact can take out a door panel, or the impact to the panel can misalign the door, creating a gap between it and the doorframe. These gaps can allow hundreds of energy dollars to escape each year.
Furthermore, the most important part of the door—the side weatherseal—is mounted to the doorframe, making it vulnerable to being torn off by a passing forklift.
The following are seven ways to maximize energy savings in the dock area.
1. DOOR VERSUS FORKLIFT The easiest and least expensive solution to forklift damage is to replace the lowest door panel, the part of the door most often damaged, with a breakaway bottom panel. However, if damage occurs at all points of the dock door or track, the best approach is to replace the entire door with a fully impactable dock door (Figure 1).
On this door style, the rollers and sheet metal tracks are replaced with retractable plungers and a V-groove track. When a door is hit, the panel can be knocked out of its track undamaged. A quick pull on the retractable plungers resets the panels and the door is back in operation quickly. No loss of energy due to door damage. No calling the dock door repair company. No disruption to the supply chain.
2. SEAL THE DEAL Using doors with compression-style seals mounted to the door panel instead of the jamb will keep the weatherseal out of harm’s way (Figure 2). This provides a consistent seal comparable to a refrigerator door—which is how many of these dock doors function in a cold storage facility. Choose impactable dock doors that have this style of seal.
3. AVOID THE DRAFT ON THE DOCK FLOOR Standard, pit-mounted dock levellers provide safe trailer access for forklifts, but their design creates passageways for air infiltration and escape. There is typically a small gap between the concrete pits and the edge of the dock leveller, exposing the facility to interior and exterior airflow exchange.
Both new and existing pit-style dock levellers can be outfitted with an advanced weatherseal system comprising a combination of durable open-cell foam and heavy-duty vinyl (Figure 3). This system effectively fills the gaps around the sides and rear of the dock leveller, providing a superior seal around the perimeter. For additional protection against energy loss, the underside of steel dock leveller platforms can be coated with spray-foam insulation to minimize the platform’s ability to conduct heat.
4. HUG THE TRUCK Most facilities have dock seals or shelters to close the gap between the truck trailer and the dock door. They are subjected to damaging force and compression when the truck backs up to the wall.
Dock seals and shelters are critically important in containing conditioned air in the dock areas. As with damaged dock doors, a poorly specified or ill-fitting seal or shelter also permits considerable infiltration.
Dock seals are equipped with fabric-covered foam pads that compress when the trailer backs into them, providing a tight seal around the sides of the trailer and closing the gaps between the trailer’s door hinges (Figure 4). Dock shelters consist of fabric attached to side and head frames, creating a canopy around the full perimeter of the trailer and allowing full, unimpeded access to the interior of the trailer.
5. LOOK UP AND SAVE High-volume low-speed (HVLS) fans improve worker comfort, contribute to energy savings, and reduce the size of the building’s carbon footprint in many different ways (Figure 5):
• Thermostat settings: Most HVLS fans destratify the air, lowering temperatures in the summer and raising them in the winter by about 5-8 degrees near the floor level.
• Reduced HVAC strain: When fans are used to move the air, the HVAC system does not have to work overtime to maintain the desired temperature, saving energy as well as HVAC maintenance and ductwork.
• Low electrical draw: Fans move a massive amount of air using a small amount of electricity.
6. SEE THE LIGHT It is generally acknowledged that, when it comes to energy savings, lighting is a no-brainer. Proper lighting is important for safety—both on the dock and inside the trailer—to prevent injury and product damage. Changing out incandescent lights with LED bulbs can save energy significantly—by an estimated 69% (Figure 6). For example, switching out 100 incandescents with LEDs can save nearly $60,000 over the life of the bulbs.
Dock managers can choose to change out just the bulbs or install a new light arm and head. Some fixtures are ruggedly designed specifically for the dock area.
7. SAVE WITH SCHEDULING In a three-shift facility, trucks may be parked in the doorway most of the day for loading and unloading. Even when a forklift operator is working as fast as possible to load or unload a trailer, the door is fully open and the dock is exposed to outside air for hours at a time.
Facilities can reduce idling time that wastes fuel with good scheduling software. Making sure a doorway is always available for scheduled truck deliveries minimizes idling time and fuel waste.
As concluded in the MHIA survey results, the movement to go green is not a fad or a passing trend in the supply chain. It is growing, and it is here to stay. Changes at the loading dock can be among those that help manufacturing plants and distribution centres move closer to their sustainability goals.
Steve Kalbfleisch is the loading dock application manager with Dock Products Canada, and can be reached at firstname.lastname@example.org.
Impactable dock doors ensure these doorways are continually protected despite forklift collisions. The guidance system enables the door panel to be pulled back into place in seconds, avoiding disruption at the loading dock.
Seals on the 206 doorways at the Canadian Tire distribution centre in Coteau-du-Lac, Que., prevent the loss of energy from this massive 1.5-million sf facility.
To prevent air infiltration through the floor, both new and existing pit-style dock levellers can be outfitted with an advanced weatherseal system comprising a combination of durable open-cell foam and heavy-duty vinyl.
A hydraulically actuated vehicle restraint is installed in the pit under the leveller and retracts into the dock wall, firmly holding the vehicle to the dock. For Canadian Tire, this means no interference with the snow plowing that takes place regularly in winter.
High-volume low-speed fans are a modest investment in keeping docks cooler in summer and warmer in winter.
Changing out incandescent lights with LED bulbs can make a significant difference in energy usage. This lighting technology can provide a reliable source for safely illuminating the loading dock and the interior of truck trailers.
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