They range depending on what types of items are being stored, which could be boxes or pallets, and the method of stocking, which is either done by workers or lift trucks. Regardless, storage racks are used across every industry that shelves extra or unused materials, parts, tools, equipment and packaging.
Industries using storage rack systems include the food and beverage processing, restaurant, electronics, pharmaceutical, farming, plastics and metal fabrication, medical and construction industries, among many others. Most systems are made out of metals like steel, aluminum or titanium because they are strong, durable and can withstand harsh industrial conditions. Some rack systems are mobile, and can be moved with the use of casters or are on a system of tracks, allowing each shelf to move in a linear direction.
Efficiency, effective use of space and organization are the three main factors when designing a storage rack system. Workers must be able to quickly and safely load and access the items when needed. The racks must be large enough and the appropriate configuration to hold the certain type of items, and strong enough to support their weight continuously for long periods of time.
There are two different methods to stocking and picking items in storage, which are commonly pallets or large boxes. The first is FIFO (first in, first out). This technique separates the stocking, which is done in the rear, and picking, which is done in the front. The storage racks usually have depth and are able to hold a large amount of pallets or boxes at once.
These shelves are often a series of rails or rollers that are situated on an incline. This way, when the front load is removed by a forklift, the rest of the items automatically move forward and waste no space. FIFO is often used with perishable food items that could spoil or expire, and keep inventory from getting lost or buried inside the shelves.
The other method of storing inventory is LIFO (last in, first out) and is mostly used for push back racks, which are also on a slant, but are positioned in rows of two, without an aisle between them. This eliminates the option to stock from the rear, leaving one aisle space to stock and pick from. Since products can sit for long periods of time in the back of the shelves with LIFO, it is used for only non perishable items. The main benefit is the space saved from less required aisle space and the ability to double up the shelving.