Each day, 30 trailer loads of product leave the distribution center at Cascades Tissue Group-Wisconsin, a private-label producer of paper goods in Eau Claire, Wis. Heavy rains and snow melt interfered with trailer loading on some of the facility’s 18 shipping docks. Water getting past the dock seals collected on the floor at the rear ends of trailers, soaking floor-loaded cartons and causing significant product damage.
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The 20-year-old, 120,000-sq.ft. distribution facility operates 24 hours a day, shipping napkins, bathroom tissue, paper towels and facial products to customers that include national and regional retail and grocery chains.
About 30% of the loads are palletized, but the balance of product is shipped in shrink-wrapped loads of corrugated cartons carried by lift trucks fitted with clamp attachments and placed directly on the trailer floors, according to Deb Creaser, logistics and distribution center manager at Cascades Tissue.
The water intrusion problem mainly affected some of the 11 loading docks on the building’s south end. Detached trailers supported by landing gear sometimes tilted back toward the dock, so rainwater ran along the trailer roof and down into the building.
Furthermore, a rippled surface on the building’s concrete exterior produced vertical channels for rainwater or snowmelt to drip behind the dock shelters and onto the loading dock.
“We did preventive maintenance every year, but that became more difficult as the facility aged,” Creaser reports. “In the summer, when it was raining, we could have as many as three or four docks that were unusable because of the water coming in at the doors.” In the winter, snowmelt resulted in a similar but less serious problem.
During heavy rains, water dripped onto cartons of product and, more seriously, collected on the trailer floors. There, it soaked into the bottoms of floor-loaded cases, which weren’t protected by the shrink-wrap.
“If it was raining hard, water could damage as many as five or six cases – essentially the bottom layer of the load at the rear of the trailer,” says Creaser. “Usually, when a case got wet, it wasn’t salvageable at all. We simply had to dispose of it. At an average value of about $30 per case, that adds up to significant losses over a year.”
To prevent those losses, shipping personnel would close the affected docks until the weather cleared.
“We would end up moving trailers and shuttling product back and forth,” Creaser recalls. “We had the warehouse set up so that certain product was staged on the north end and certain product on the south end. If we couldn't use certain docks on the south end, we were forced to shuttle that product much farther within the distribution center.”
In summer of 2004, Creaser and the Cascades Tissue management team tested a Frommelt RainGuard RG-3000 header seal, supplied by Rite-Hite Corp. (www.ritehite.com). The unit was installed over the existing dock seal on one dock at the building’s south end. The local Rite-Hite representative, Pugleasa Company Inc. (www.pugleasa.com), custom mounted the unit to seal the vertical channels in the building wall.
The system’s basic design keeps any water flowing along the trailer roof from entering the building. A weighted, cylindrical sealing element provides uniform sealing pressure across the full trailer width.
The seal provides 15 in. of trailer coverage, sealing the tops of trailers from 12 ft. 3 in. to 13 ft. 6 in. tall, and exerts the same pressure, regardless of trailer height. It provides an effective seal on the 53-ft.-long dry vans and taller high-cube trailers that visit the Cascades Tissue dock.
The RainGuard unit automatically adjusts to the proper trailer height, and a pivoting canopy header protects it from damage by trailers that back in off-center and higher than expected. Tough Neotec HMWPE front impact plates take the hit from backing trailers, protecting the sealing member and ensuring years of reliable life.
The rain diversion seal was so effective during the pilot test that in summer 2005 the firm installed four similar units on the south-end docks, where water infiltration had been the most severe. Cascades Tissue now can use all its shipping docks regardless of weather.