Pallet Selectivity vs Pallet Density

  "Maximize pallet count". This is a phrase we hear all of the time. "We're paying for all this cubic space – lets fill it up!" As in most things in life – it's just not that easy.

Pallet Selectivity

There is a rarely a case when a user does not prefer access to all pallets all the time. Single deep, Selective racking fits this need and is the most common rack set up in America. The most common fork truck is the sit-down propane or elective powered truck designed to work in a standard 12' aisle single deep selective rack system. So, what is the problem? Pallet density lacks. For every rack face you need an aisle to access. There is more aisle than racking in a standard 12' aisle system.  Options include (note: special equipment needed to reduce aisle):

• Narrow Aisle – Stand up reach trucks can reduce aisle size down to 8'
• Very Narrow Aisle = Turret trucks can reduce aisles to as little as 65"
• ASRS (automated storage and retrieval) – Cranes are incorporated in this very narrow system and pallets are pulled via software guiding cranes

Pallet Density

How many pallets are you trying to store? Simple question and good starting point. But if the answer is 500 for example does that mean 500 different items or 500 of the same? Or more than likely somewhere in between. If a solution is miss applied "honeycombing" can occur. This is where there is a pallet location available for storage, but it remains open because product could not be mixed in the same lane. Access is needed without moving another pallet(s). Examples of multi-deep racking

Drive-In Racking – Lifts literally drive into the system and pallets are held on outside edges one angle or channel. Pallet consistency in width and quality is a must. This is the least expensive multi-deep system but also the least desirable. There is limited selectivity vertically – to access a level above pallets must be removed below.

Push-Back System – Allows each lane to be accessed separately.Stacked carts roll on rails and push back to expose another cart below. Up to 5 deep is most common. 

Pallet Flow Racking – Pallets are placed in one end, they index downstream and removed from far end. Normally not more than 15 pallets deep.

Pallet Shuttles - These are smart systems that retrieve pallets via shuttles and bring them to a unload  location. This technology is still relatively new but shows great promise. This solution gives both pallet density and selectivity at a price point that is becoming more and more desirable.

What is right for you ?? The ideal solution is often a combination of the above. It is common to identify products that you have an average of 4-5 or more on hand at all time. And those that there will most often be 3 or less.  After you break down your product mix the solution becomes more evident. Of course, future estimates must be considered as well.

Of note: We often enter a warehouse that is floor stacking pallets – sometimes 3 or 4 high and 5-15 deep.A good example is pallets of the same product all placed together and normally shipped in bulk or large quantity. In a lane 4' wide x 60' deep lane there may be 45 – 60 pallets of the same product. We will be asked to increase storage space using a rack system. This is not easy – the simple single deep system would create too much aisle space – pallet capacity would most likely be reduced (selectivity gain but at a huge pallet count cost).  A very narrow aisle or multiple deep system requires a significant monetary investment that often is not justifiable.

Confused? That's where McGee Storage and Handling can help. McGee offers consultation that is most often free of charge. Together we can build the right system – www.mcgeeatlanta.com and/or call 770-458-4346