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INCORPORATING COLD CHAIN |
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specialisation . Mobiles still have manual input , but the mobiles can be moved automatically , controlled by the warehouse management system . Mobile racking has been described as the sweet spot in the move towards automation . With immediate individual pallet access , the pallet itself doesn ' t move . A warehouse management system is particularly well adapted to this scenario , but less so where the pallet can change position , such as in shuttle or drive in racking systems .”
As to which racking system is appropriate , Cunningham says : “ It ' s a matter of scale . If a business has a store 4m high and needs some racking , a mobile system is probably not the answer . Where a warehouse is 12m high with a need to get in as many pallets as possible , then mobiles demand consideration . It ' s a matter of how many pallets a business wants to get into the store . We have put in mobiles at two-pallet high applications , because the warehouse manager was happy to double what was previously possible and it was financially viable at the time .”
One has to bear in mind how far the racking industry has progressed . “ In my first job at an old-style ( more than 30 years ago ) freezer store , when racking was installed we effectively doubled our productivity . Then with a warehouse management system we doubled it again . Thereafter , in a freezer store if fixed selective racking is replaced with mobiles , irrespective of narrow or normal reach truck aisles , storage capacities can again just about double .”
The pay-back on mobile racking capex varies entirely on circumstances . “ We had an
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instance where a poultry company wanted to build a new warehouse . However , their existing facility , built 10 years earlier , had mobile rails in the cold store floor . This had been overlooked . We showed them that by utilising the rails for a mobile system they could achieve exactly the same additional storage as the proposed new facility . The retrofit paid for itself in under a year .
“ Consequently , we always suggest to customers who are building freezer or chilled stores to put mobile rails in the floor , even if they install static racking to start with . It ’ s much more difficult to install rails later when the need for storage capacity increases ,” says Cunningham .
SETUPS , HEIGHT AND WEIGHT FACTORS
If a customer ’ s operation needs require a higher warehousing capacity , there are a number of options that can be applied – standard racking can be re-designed to handle any pallet weight , for instance by the addition of stronger beams .
Standard sizing of frames is the norm , but they can also be tailor-made for the customer utilising odd-shaped pallets , for example 1500mm x 1200mm . Everything is customisable as the product is generally modular in nature .
Facility layout and racking design is predicated on the customer ’ s predetermined strategy . The elements that should be considered from the outset include : the potential for future expansion or upgrade , the dimensions of the property and consequent spaces for storage , the equipment to be used and flow of traffic .
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Over the past years , most companies have adapted their storage facilities to higher racking and today it is not uncommon to see installations anywhere from 7m – 14m high , and designs catering to a maximum pallet weight or tonnage per bay .
The racking itself can consist of many variations in frame size and beam dimension , partly depending on how many pallets are loaded per rack compartment . Some applications have two pallets per pair of beams , with either the short or long side of the pallet facing the access aisle . Gross pallet weight is another consideration as well as the number of pallet levels in the height . Generally , the higher the racking the greater the loads imposed on the frames . Open bay widths should increase with height to widen gaps between the pallets . But increasing the number of pallet levels ( within reason ) also reduces the freezer footprint . ‘ Higher ’ freezer stores tend to have a lower capital cost per pallet position created than lower ones with fewer pallet level .
Rack frames include bracing to keep the rack uprights at the right distance apart . Different bracing patterns can change the loading capacity of rack frames but such design aspects are now increasingly computer generated . As a general rule though , a rack user should never change bracing patterns or beam levels without first speaking to the company that supplied or manufactured the racking .
There is also a structural difference between mobile and static options . On mobiles they have to be able to work with dynamic loading ( which is that they are moving ), whereas the fixed racking stays in
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EP Refrigeration
Any commercial store must accommodate for growth and future diversification in products that may have differing weights .
one place so the design criteria on mobile racking needs to be more robust that the static solutions . CLA
REFERENCES : 1 . Cold Link Africa , July 2021
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