Types Of Storage Systems
It is important to select the appropriate storage system. For instance, we will need to ensure the safety of the goods and the labour. In order to select the most suitable system, we will need to match goods storage and its throughput requirements to the equipment characteristic. There may have to be a compromise between maximising the use of space and the need for easy and quick access to the stored goods.
There are many types of storage systems. They can be categorised into racking system, shelving system etc...
Block Stacking
In block stacking, no storage racks or supporting structure is needed. This storage system is used for storing large quantities of palletized or boxed products by placing it directly on the floor and put it in stacks (placing the items on top of each other) or in rows (placing the items next to each other). Common use in paper industry, household products and reserve storage area. Items are retrieved on a LIFO (last-in-first-out) basis. Depending on the weight and stability of the loads, stacks may range from two loads high to a height determined by: - Acceptable safe limits
- Load stackability
- Load weight
- Pallet condition
- Floor loading restrictions
- Weather (due to corrugated softening in high humidity)
- Vehicle lift height capacity
- Crushability of the loads
- Building clear height
Advantages - Low capital cost
- No storage equipment needed
- Suitable for high throughput items
- Minimum cost of storage since cube utilisation is high
Disadvantages - Material accessibility is low since only top of the front stack is accessible
- Limits on stack height (depend on the loads at bottom of a stack to support the imposed weight)
- Vulnerable to fire risk
- No strict FIFO (first- in- first out)
Selecting Racking The following will have to be considered: 1)Pallet (or for the product being stored): - size
- type
- construction
- capacity
- security
- stability
2)Handling equipment: - type
- maximum lifting height
- dimensions/aisle width
3)Storage area: - dimensions
- type and construction
- floor loading, capacity
- obstructions, exits, stairs, etc.
- floor fixing facilities.
4) Goods: - type
- frequency of movement and access
5) Safety: - fire protection requirements
- fire exits
6) Specialist requirements - equipment
- accessories
- protective
Adjustable Pallet Racking (APR)  Adjustable pallet racking (APR) is the most common type of racking. It is adjustable with the horizontal beams between the vertical uprights, the uprights being fixed securely to the floor. Accordingly, with APR, different pallet heights can be accommodated, but different length/width dimensions cannot be covered by adjustments to the beams as the length/width is determined by the floor area fixed upright positioning. Adjustments to the beams are not easily made, however, as the beams are solid structures held securely by pins that need to be manually moved and repositioned. Clearly the beams/racking must be empty while this is being done. As stated above, with APR the floor space utilisation is low as APR needs relatively wider aisles to allow product access.
Wide-Aisle Pallet Racking System
 As shown in the diagrams, pallets are placed a minimum of 2.5m wide between each other so as to allow vehicle to drive through for easy loading and unloading. In addition, it also allows a large volume of products to be stored. No specific requirement of any handling equipment. However, a normal forklift truck would not be recommended due to the height restriction. This system is used when the warehouse has a restriction for low-level picking. Besides that, this system could be use when space utilization is not critical as it helps to smooth the flow of goods, ease of loading and unloading and also gives fast throughput.
Advantages
-It is one of the most commonly used systems
-For storing palletized unit loads
-Pallet arrange in wide aisle pattern
-No specialized handling equipment needed
-Fast throughput ease of loading and unloading
Disadvantages
-Utilize only 40% of the floor space
-Incurred high storage cost
-Less storage place
Applications
Any situation when space utilization is not crucial. Most retail grocery distribution centers have wide aisle storage systems. For products that require a storage system that is capable to cope with the high environmental uncertainty.
Narrow-Aisle Racking System
This system has aisle around 1.7m wide to save up space. In addition, it frees up to 45% for the floor space given over to aisles in a wide aisle scheme. The net result is a dramatic increase in space utilization. Each pallet is supported which means that stock rotation and accessibility is as good as a wide aisle system. Furthermore, this system would only be suitable with a narrow aisle forklift.
Advantages
-Saves space
-Save cost as less storage space
-Easy access for loading or unloading equipment
-Easy access to product
-Easy stock rotation
-More floor utilization compare with wide aisle racking system
-Fast throughput
Disadvantages
-Only small volume items are to be stored due to the limit in aisle space
-Need truck guidance systems
-Specialize forklift needed, thus increase set-up cost
Applications
It is suitable for applications such as electrical goods, hardware parts and components. Products are stored in pallet lot size. In addition, the products are withdrawn as the same way they were stored.
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