A Bit of History
Cold stores with insulated sandwich panel construction became popular in the 1970’s. Prior to that they were insulated with cork and low in height. As clear heights increased so did capacities and pallet access problems began. The norm in relatively low cork stores was to block stack product sometimes not even on pallets. As store heights increased, converters or steel frames were introduced to improve stability and prevent crushing to the lower layers of boxed product. Capacity utilization was good, but access to product and stock control accuracy were terrible. In freezers of 2000 tons plus, stock could be lost for years, hence the acronym FISH, First In Still Here.
Fixed selective pallet racking was initially introduced in higher volume throughput distribution freezers with high numbers of SKUs and an element of case picking. Fixed selective racking was great for pallet access but bad for holding capacity as half the expensive volume was lost to access aisles. Racking developments since then are designed either for high density or pallet access. “Drive in” racking is high density as is “push back” and “flow racking”. “Fixed selective”, “narrow aisle” and “high bay crane racking” are geared for individual pallet access.
But modern freezers are expensive both to build and to operate and given the growth in product lines, racking systems must offer both high capacity and great access. This is what mobile racking achieves. Mobile racking was first installed in 1990 at Hermanus Seafood, and has become almost standard in new freezers since the early 2000’s.
Things to consider when choosing and operating your freezer racking system.
- Don’t compare racking costs in isolation. Fixed selective racking may be “cheaper” than mobile racking but the effective storage capacity of the store will be halved. When you divide the total capital cost of the freezer (including the racking cost) by the number of usable pallet locations, more expensive racking types can be surprisingly cost effective. As freezer stores are rarely turned off, consider allocating a bit more to the initial racking budget to increase flexibility later. This can pay dividends in the future.
- Design the racking to carry heavier pallets than are initially expected. Consider installing mobile rails and mobile friendly fixed selective racking so that your freezer capacity can be quickly doubled when required. Consider the use of pallet support beams on higher pallet levels. There is nothing more difficult than trying to remove a broken but wedged pallet at 9 meters in -25 Degrees C.
- Not nearly enough attention is paid to racking inspections and repairs. Freezer stores are uncomfortable places, so there is even less incentive to spend time checking for rack damage. Rack inspections should be carried out weekly by on site trained personnel and by an external expert once every six months. All rack repairs in freezers should be inspected by a third party and signed off before being used.
- Don’t make access aisles too narrow. Squeezing them may allow for an additional run of racking, but the additional storage capacity will be accompanied by increased rack damage.
- Make sure your freezer store drivers are well protected from the cold. Reach trucks and forklifts without heated cold store cabs may be cheaper, but semi-frozen drivers are more likely to damage racking. At least spend a bit more clothing wise to protect them from hypothermia.
- Always maintain clear spaces between the rack frames and the loaded pallets as well as between the pallets themselves. Leaning pallets, especially when in contact with rack frames are particularly dangerous. Removing such pallets from the racking at high level can result in falling product while also exerting negative forces on the rack frames.