Typical security cages are static, chain link-walled compartments that are lockable and camera monitored. Access can be by physical or digital locks. The latter is often preferable because a log of successful and unsuccessful access attempts will be created, and operatives can be given single-instance or timed access. Cages can be wire or solid bars. The spaces in the cage walls allow for visual checking of contents. For added security, cages are often located in line-of-sight proximity to a supervisor’s office. High-value, controlled, and hazardous substances may be used to stored in cages, to deter pilfering and reduce the possibility of breakage or mispicking. Some cages, such as those used in the airline and duty free industry, have a wheeled base, so can be moved manually, which creates a security risk. Most have no top coverage, so products that are touching the sides can be manually manipulated, by fingertip through the chain links, upward to the open top, where they can be nudged over the walls. Caged items are often lost this way. For this reason, duty free items are often packaged anonymously.
Small items that need to be located easily and quickly, can be picked by fingers, and are picked frequently, are suited to storage in bin bays. Companies with onsite workshops often use bin bays to store components for products being assembled and to send to customers who require spares or replacement parts. Bins can hold products of various sizes and materials, such as plastic and metal, but are open-faced and therefore unsuited to the storage of hazardous, controlled, fragile, temperature- or humidity-sensitive, perishable, or oxidisable items. Large, heavy items can be unsuited to bin bay storage, because most bin bay picking is manual; bins require the picker to reach inside and lift out items by hand. Mechanized bin bay picking exists, but is a highly specialist, expensive operation. Bin bays are rarely ideal for items that have to be stacked or placed in an ordered manner. They are better suited to the storage of durable items such as hardware. Bin bays can also be positioned on weight sensors that monitor the quantity of items in the bin. The sensors can trigger replenishment orders from the appropriate supplier and the order’s delivery can be timed so that replenishment occurs before stockout. Also, in a well-designed bin bay system, the bins are located according to the frequency of pick, with the most frequently picked items stored in the bins closest to the entrance or the serving window, which is usually directly above the operative’s desk. Bin bays are visually identical, so must be very clearly labelled. Colour coding and zoning can increase the efficiency of picks. Operatives only require an approximate understanding of the item being picked (e.g. hardware, electronic, fastening, etc.) in order to locate the zone in which its bin will be located, which speeds up the pick considerably.
Pallet racking is convenient for the movement of goods that are palletized on delivery and are despatched palletized. For this reason, they are often found upstream in the supply chain, where bulk does not need to be broken; rather than downstream, where loads are increasingly separated for individual customer orders. Exceptions to this occur in supply chains where product remains palletized until it reaches the end consumer. Furniture, boilers, and other bulky and heavy items fall into this category. Pallet racking is simply shelving that is sectioned and dimensioned to accommodate pallet loads. Its shelves are extremely strong and its sections (or “bays”) are of the correct width and depth to comfortably accommodate standard pallet-sized, still-palletized loads. Loaded pallets are placed and picked by forklifts. Pallet racking is particularly saving of floor space, which is usable for palletized loads that can be stacked directly on one another. Palletized loads that cannot bear any top compression must be placed unstacked on floors, which takes up valuable space and exposes the items to collision and other hazards, or stored on pallet racking, which is in every way the superior option. However, pallet racking installation is expensive and the footprint of the facility must be large, if the volumes that pass through it are high. When palletized loads are uncommon however, a small section of pallet racking, among general purpose racking, may be sufficient. If the pallet racking shelving goes to several vertical levels, specialist forklifts and forklift operator training may be required, and additional safety and construction requirements may have to be met.