Quick guide to warehousing - methods

Welcome to Part 2 of our new blog series, designed to help anyone new to searching for warehouse space understand any terms they are not familiar with. In Part 1, we covered Types of Storage. In this blog, we turn to Methods of Storage and in Part 3, Ancillary Services. Finally, Part 4 will give an overview of Distribution Services.

If you can’t wait for the subsequent parts, you’ll find short explanations of many of the terms we cover in our glossary .

We do not currently offer bulk stacking but will be developing that in future.

Bulk Racking

‘Bulk racking’ generally refers to racking which carries bulk stock in full pallets (as opposed to picking stock discussed below). Where picking stock is also held, bulk stock might also be referred to as back-up stock, although back up stock (and bulk) may also be stacked multi-high and multi deep in a non-racked area.

Full pallets will be held in ‘standard’ size racking bays. For ‘standard’ there is not a particular standard but most racking bays will be between 1.5m and 2m high, more generally around 1.65m high so as to accommodate the vast majority of pallets (with the height of the vast majority of pallets governed by they being able to fit two high in an articulated vehicle). A bay’s width is determined by the distance between the uprights, but generally this is around 2.7m, allowing for 3 euro pallets or 2 standard pallets. Where a warehouse is handling heavy product, bay widths may be less to increase the weight capacity of the horizontals.

Generally, a warehouse will have racking up to its ceiling, and have handling equipment – reach trucks – to service this. For most warehouses, this will be 4 or 5 racks high, including the ground rows. Sometimes the top rack may not be full height and designed by need or necessity for half pallets. Where a warehouse has a significant number of products held in smaller, perhaps half-height, pallets (possibly because they are low sellers) it may have an area of racking specifically designed so as to optimise space utilisation.

Picking Racking

Picking racking, sometimes call pick-faces, contains the pallets from which single or multiple items are to be picked for orders, rather than whole pallets. For efficiency, these are on the ground level or first rack – as much as space and product complexity allows – so as to allow hand picking rather than lowering pallets from higher racks to pick a unit or two and then returning the pallet back up.

Again, where appropriate, half height racks might be created to enable more pick faces. Where items are really low seller, several may be combined on a single pallet.

As a pallet of a certain item is emptied, a full pallet is retrieved from the higher racks to replace it. For fast selling items, there may be two or more pallets in the pick faces to ensure the product still available to pick whilst a further pallet is being retrieved.

Stacked Product, or Bulk Stacking

Stacked product refers to pallets that can be stacked on top of each other, perhaps up to 4 high, depending on the pallet’s stability and the warehouse’s equipment. Pallets intended for stacking need to be such that the weight of the pallets, backed up by the type of product packaging, does not damage the product; as well as being cuboid. Sometimes, pallet boards – usually chipboard or similar – are used between the pallets to protect product and spread weight.

Generally, only the same product will be stacked on each other to ensure the bottom pallet is not needed next.

Zupplychain does not currently offer bulk stacking but will be developing that in future.

Roll-in, Roll-out

Or ‘drive-through’ racking. This system enables pallets to be stored one behind each other in racking, thus saving aisle width. New pallets can be added at the back of the row, pushing the existing pallets forward on tracking within the racking. This would be used for the same product and allows a FIFO (first in first out) system to be run. Roll in roll out is suitable for relatively fast moving whole, full pallet in full pallet out, product.

Very Narrow Aisle (VNA) Racking

Very narrow aisle racking is the use of selective pallet racking in a tighter configuration to provide maximum space utilisation within a warehouse. These systems typically operate in conjunction with wire-guided or rail-guided specialised reach-trucks, like a guided bus lane. The advantage of VNA is fast picking without large aisles which results in improved use of space.

Automated Storage and Picking Systems

Automated systems tend to be used by businesses with high range complexity, high picking complexity and relatively small sized products. The items are kept in boxes or trays rather than pallets and sometimes in buildings much higher than a standard warehouse – or partially underground, as height is not limited by maximum fork lift reach height.

Computer systems then optimise the automatic picking mechanisms which either collate the items of an order into a single box or tray, or bring down the relevant box for single item hand picking in a pick and pack area.

Automated systems are nearly always bespoke designed for a manufacturer or distributor’s specific needs and represent significant investments.