By Klaus-Dieter Wurm, March 4th 2013
Learn how to design a better pallet storage system for freezer warehouses, doubling storage capacity while cutting lift truck maintenance expenses and labor costs dramatically
In freezer warehousing, the primary cause of lift truck equipment failure is condensation caused by the constant in-and-out movement of product by lift trucks operating between the freezer’s -20° F temperature and the loading dock’s ambient air temperature - which in many parts of the country can exceed 100° F in the summer. The extreme temperature swings cause moisture to aggregate, resulting in the failure of electronics, electro-mechanical components and wiring.
The only solution preventing condensation in freezer warehousing is keeping lift trucks inside the freezer. However, OSHA regulations require lift truck operators to leave the freezer environment every 15 minutes for warmth - causing a demonstrable 50% productivity loss. This has resulted in the design and use of fork lift trucks with heated cabins. These lift trucks never leave the freezer warehouse, allowing operators to be both warm and productive during an entire shift.
So, if the fork lift truck never leaves the cold store, how do we store pallets and how do we pick and ship pallets? The answer is pallet conveyor technology with in-bound and out-bound spurs. Whether unloading a tractor trailer or moving pallets from the production area into the freezer warehouse, pallets are placed onto the pallet conveyor outside the freezer and enter the freezer via high-speed dock doors. These dock doors are just large enough to accommodate the size of the pallet, allowing pallets to quickly enter the freezer warehouse. The dock doors quickly seal the entry point to minimize warmer exterior air entering the cold store. Today’s freezer warehouses typically use large “barn-size” doors equipped with plastic strip curtains at ingress ostensibly to reduce the constant cross-contamination of warm air entering the freezer. However, the constant movement of lift trucks in and out of the building actually creates the opposite result – heat and temperature variation.
It is much more expensive to cool air than it is to heat air
Two choices - automating freezer warehouses and keeping lift trucks inside the freezer - can reduce the energy consumption by as much as 80%, and can reduce labor costs by as much as 70%.
Once the pallets have entered the freezer warehouse via the high-speed dock door, the pallets travel on the pallet conveyor to the pick-up point, typically located in the middle of the building at the center aisle. The lift truck picks up the pallet at the end of the conveyor line for put-away, thereby reducing the travel time due to the much shorter distances between pick-up and storage locations. Using conveyor technology also results in considerably lower labor costs because the same throughput can be accomplished with fewer operators. And, lift truck wear-and-tear is significantly reduced by the shorter travel distances. Outbound picking – in which pallets are placed on the outbound conveyor instead of moving pallets the entire warehouse and then through the large strip curtain door to the loading docks – also results in much shorter travel distances, less lift truck use, less wasted time: lower costs.
The other component of a better cold store design is better storage technology, more specifically a high-density storage system. A typical cold store utilizes selective pallet racking technology with aisles widths of up to 12 feet. [It should be mentioned that VNA (Very Narrow Aisle) Racking can reduce the aisle width to 6 feet]. With any freezer warehouse storage system having aisles for lift-trucks to maneuver and turn-around, a very important question should be asked: “what are we really freezing?” The answer is air and aisles. With the cost of energy, real estate and labor constantly increasing, freezer warehouse owners should look at new paradigm-shifting technologies such as high-rise ASRS systems, or better yet, Mobile Pallet Racking technology, which uniquely addresses building and warehouse heights under 30 feet. Mobile Racking in freezers is very common in South America and Europe; by some estimates, 95% of all European colds stores are equipped with Mobile Racking. Mobile Racking uses conventional selective pallet rack mounted on carriages and moving on running rails and guide rails embedded into the concrete floor. Since electricity expenses in a freezer warehouse are second only to labor costs, it makes sense to double the amount of pallet locations inside the building. This gets back to the question: does the warehouse owner want to freeze product or freeze aisles? Doubling the amount of pallet positions can reduce the total cost per pallet position by as much as 40% in new construction projects, and can reduce the utility bills by as much as 50%.
What if you do not need more pallet storage locations? High-density storage solutions such as Mobile Racking result in a much smaller building footprint – for an up to 45% reduction in real estate requirements. A significant reduction in energy loss (and utility bills) also ensues, due to the correspondingly-smaller roof structure reducing air escape. The other cost savings of a smaller, more efficient Mobile Racking warehouse include a 35% lower overall investment in construction costs and a reduction of up to 49% in utility costs.
Mobile Racking is a pragmatic, smart, state-of-the-art solution for freezer warehousing. Join Euro-Bake in St. Petersburg, FL, Anthony Cold Storage in Newfoundland, CAN, or Ditzler Ltda. in Santiago de Chile, Chile (the Ditzler Mobile Racking is a “highly seismic compliant” installation), or any of the other 1,500 highly-satisfied Mobile Racking customers worldwide and discover why SSI Schaefer should be your company’s solution!