As an operator of one of the few fully air-conditioned production and distribution facilities in the Columbia, SC, area, Select Comfort Corp places a high value on employee comfort. Yet the company also understands the need to control the 110,000 sq ft facility's energy costs, especially during the Palmetto State's hot, sticky summers.
To achieve the best of both worlds, Select Comfort recently installed new, energy-efficient Frommelt Eliminator-GapMaster II loading dock shelters at just over half the facility's dock positions. The result is a much cooler and more comfortable working environment, as well as annual energy savings in excess of $12,000 -- with the potential for additional savings as more docks are upgraded.
A Beehive of Activity
Select Comfort is best known for its patented Sleep Number® adjustable firmness beds, sold at retail stores and through a national direct marketing operation. The company's manufacturing and distribution facility in the Columbia suburb of Irmo, which employs about 200 people, produces and ships beds to stores and individual consumers in the eastern half of the United States.
The Irmo facility's 18 loading docks handle about 20 semi-trailers a day, seven days a week. Darin Swiger, Irmo facility order fulfillment manager, said that shipping department employees work 10- to 12-hour shifts each day. Shipping activity kicks into high gear at noon every day as United Parcel Service begins picking up loaded trailers for next-day delivery to customers.
According to Swiger, the air conditioning system didn't seem to keep the loading dock environment at an even, comfortable temperature throughout the day. The uneven temperature was also a suspected cause of high air conditioning costs.
"One side of the plant was relatively warm and the other side was much cooler because it was away from the doors," Swiger said. "After awhile, we decided to take another look at the temperature fluctuation to see why it was happening, and more importantly, if there was something we could do to fix it."
The Irmo facility was experiencing the effects of "white space" -- spots of open air around parked trailers at loading dock doors. The cause of the problem was relatively easy to identify: dock shelters and seals battered from nearly 20 years of impact by semi-trailers.
"The dock seals we had were in very bad shape," Swiger said. "You could see sunlight through them, and on some days, the heat would make work conditions very uncomfortable for those loading and unloading trailers."
Another big problem was the exposed space created by the hinge gaps of open swing-out, semi-trailer doors. The 1.5-2 in. gaps on either side of the trailers at each dock position produced the equivalent of 2.5 sq ft holes in the wall that allowed air -- and expensive cooling energy -- to freely flow in and out.
In addition to improving employee comfort and lowering energy costs, Swiger said replacement dock shelters had to stand up to repeated impact from semi-trailers. Trailers being backed in too quickly or arriving off-center were of particular concern, he said.
"A little bump here and a little bump there shouldn't cost you $5,000 worth of damage," he said. "However, the shelters we were using could be easily destroyed if a trailer backed into them."
Aesthetics was also an issue, Swiger said.
"Some of the existing dock shelters had been modified and patched up by previous maintenance people so they just looked bad in general," he said. "I wanted to put a nice clean look to the docks, as well as seal out the air."
Finding a Solution
An Arbon Equipment representative who visited the Irmo facility quickly confirmed that the "white space" resulting from the worn dock shelters and exposed trailer hinge gaps was a serious energy-waster.
The representative conducted a custom energy loss analysis to determine how much air was leaving the building. The analysis, using methods from the American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE), factored in the local area's average temperatures, wind speeds, electricity, and natural gas costs plus the Irmo facility's door sizes and hours of operation. The analysis showed that the old loading dock shelters were contributing to a potential energy loss of hundreds of dollars for each of the 18 dock openings -- as much as $40,000 for the entire facility.
The solution called for installing new dock shelters that could seal off the exposed trailer door hinge gaps while providing full, unobstructed access to trailer loads and stopping the identified energy loss. When reviewing the options, Swiger visited a nearby loading dock operation to inspect the installation of Frommelt Eliminator-GapMaster II (EGM II) soft-sided dock shelters.
The EGM II features unique hooks on the shelter's side curtains that seal the trailer door hinge gaps to prevent airflow in and out of a facility, saving up to 85% of lost energy. In addition to energy savings, sealing the gaps also minimizes the infiltration of dust and pests. Additionally, the seals include an integral fabric-wrapped rain gutter to help divert water off the side of the shelter, helping to keep the dock area, workers, and materials dry.
When deciding on dock sealing options, Swiger also paid close attention to the EGM II's impactable structure. The slim-profile foam side frames, wrapped in a flexible sheet of durable high molecular weight polyethylene beneath an outer layer of high-wear fabric, are designed to withstand repeated impacts from backing trailers without sustaining damage. A pivoting fabric canopy header adds additional protection against damage from trailers backing in off center and higher than expected.
Savings and Comfort
Based on the energy loss analysis and seeing the nearby Eliminator-GapMaster II installation, Select Comfort officials opted to install EGM II dock shelters at the Irmo facility in two phases. In the first phase, the new shelters were installed on the 12 most worn shelters in the shipping department. The remaining six shelters will be replaced with EGM II shelters at a later date.
Swiger immediately noticed a difference, particularly as the energy-robbing trailer door gaps disappeared.
"For now, our electricity savings are $1,000 to $1,100 a month. We're anticipating even better savings as we add more new shelters -- and watch the price of energy rapidly rise," he said.
"There's no question that the shipping area has been much more comfortable and our employees really appreciate it," said Swiger. "Increased employee comfort, combined with energy costs savings and a payback of about two years when it's all said and done, make the installation of Eliminator-GapMaster II shelters a good investment. We're looking forward to installing the same shelters on our remaining docks."