Types of racking and what each suits

Racking is often chosen on price: "let's take the cheapest". Then it turns out that you must move three pallets to reach one, and long pipes will not fit on ordinary shelves. Every type of rack is made for its own job, and the wrong choice costs both warehouse volume and picking speed. Below we look at the four main types.

Selective racking

This is the most common type: every pallet can be reached directly from the aisle. Other pallets do not need to be moved, so goods can be taken freely, by expiry date or by order of arrival. It is easy to build and operate, and an ordinary forklift is enough.

The drawback: a large part of the warehouse is taken up by aisles, so storage density is low. Selective racking suits cases with many different products but a small stock of each, such as a distributor's warehouse, a pharmacy reserve or the small items of a building-materials depot.

Deep racking

In deep racking pallets are placed in rows one behind another. The forklift drives into the rack (drive-in type) or pallets are pushed in on carts (push-back type). There are fewer aisles, so noticeably more pallets fit in the same area.

This type is good when there are many pallets of the same product: drinks, seasonal stock, mass-market goods. It also suits slow sellers with a large stock. There are downsides. As a rule the last pallet in is the first out, so it is unsuitable for goods with an expiry date. The forklift works inside the rack, and the risk of hitting the structure is higher.

Cantilever racking

In cantilever racking, arms project sideways from uprights and the front stays open. This type is made for long and awkward loads: rebar, pipes, profiles, boards, sheet materials. Such a load will not fit on the beams of an ordinary rack, or becomes dangerous there.

Building-materials depots need it almost always. Cantilever racking can also stand in an open yard under a canopy. The limitation is that it is good only for this type of load, and for other goods the space is wasted.

Flow racking

In gravity flow racking the channels are fitted with inclined rollers. The load is put in at one end, rolls under its own weight to the other, and is taken from there. As a result the first goods in are the first out, which is its most convenient property.

That is why flow racking is ideal for goods with an expiry date: dairy, food, medicines. A smaller version for cartons is used in the picking zone: the picker takes from one side and replenishment is done from the back. It costs more, and each channel is assigned to one type of product.

How to choose

Answer these questions:

• How many different products are there, and how many pallets of each are stored? For many products and few pallets, selective; for few products and many pallets, deep.
• Do expiry dates or the "first in, first out" rule matter? If so, flow or selective.
• Is the product long or oddly shaped? Then cantilever.
• How high is the building, is the floor level and strong, and what forklift do you have?
• What is the budget? Selective is cheapest.

For example, if you have 40 products with 50 pallets of each, deep racking holds noticeably more pallets in the same area. If you have five hundred products with 1 to 3 pallets each, selective is better. Often two or three types work together in one warehouse.

Whichever type is chosen, the rack must be properly anchored to the floor, each level must carry a load plate, and the structure must be inspected regularly: a hit upright or a bent beam creates danger. This is covered in detail in the article on pallet storage.

Conclusion

The rack type is chosen by the properties of the goods, the stock volume and the turnover pattern, and price should be the last criterion. During a warehouse audit, SkladKontrol checks whether storage places match the type of goods and helps find where space is used inefficiently.