Choosing the right kind of pallet racking can be a complex exercise, depending on many issues like stored product dynamics and product homogeneity, floor conditions, and even knowledge of all the forklift truck types available. Usually, an overriding concern is the need to save space without compromising instant stock selectivity and so the popular choice falls on adjustable pallet racking (APR), either bolted or boltless. But when it comes to costs of each type of racking there can be misconceptions about the true costs, which should not be measured merely in terms of cost per pallet position installed. As with forklifts, it is the lifetime costs that should take precedence rather than initial cost.
Consider, for example, live racking, also known as flow storage, which is a high density, dynamic storage operated by gravity roller conveyors angled at 4%. Many operators choose this form because they do not need 100% instant pallet selectivity and favour its high density storage. Drive-in/drive-through racking offers comparable high density storage but costs less than half the price of live racking. But that big difference in cost can be cut sharply by the much higher utilisation rate of flow storage, typically 90%, compared with only 60% for drive-in racking. When other cost considerations for flow storage are factored in over, say a three-year period, like lower building and forklift maintenance costs, fewer forklifts and less staff, then flow storage can work out over one third cheaper than drive-in. Warehouse operators should also bear in mind costs from accidents with drive-in racking, notorious for pallet collapses, which could bring down an entire racking block.
If planning to use drive-in, then crucial factors to consider are careful design and installation, floor flatness, the current size and strength of pallets and the right forklift for the job. Given that pallet loads must be properly placed on beam rails, the demands on forklift driving skills are high and as with drivers changing from one type of forklift, i.e. reach, to another, like articulated trucks, who should be retrained, it is advisable to train drivers who have never worked with drive-in racking. In this regard, guidelines and codes of practice are available from SEMA.
As with all kinds of racking, safety is a big issue. There should be regular damage inspections done by trained warehouse staff, plus an annual or bi-annual inspection by a SEMA-approved rack inspector. Racking collisions are a constant risk so rack end protection and column protection, wheel guides and height restriction barriers from suppliers like Berry Systems, Rack-Guard and Addgards are worth considering and SEMA are reportedly contemplating new guidelines on such protection.
Such barriers are not all static. Berry, for example, last year launched a ‘Soft Stop’ bollard, which is a dynamic, energy-absorbing protection system. It comprises a base on which a protective pole or post can be attached. During a collision, the kinetic energy of the impact is progressively absorbed as the post tilts, crushing an elastomeric sleeve within the base. It can tilt up to 20 deg and after the impact the post returns back to its vertical position., ready for the next hit. Depending on specification, it can cope with impacts from a light pallet truck up to a 20-tonne vehicle.
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