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High Density Storage Rack Guide
(Drive-in, Drive-Through & Pushback Rack)

A Tutorial Guide for High Density Racks

Cantilever Rack

While this guide is meant to assist you in choosing your rack, it is still beneficial to consult with one of our professional solutions specialists. They have been working with this material every day for years and are aware of ALL the tips and tricks concerning drive-in, drive-thru and push back racks. Please feel free to call us at 800-598-5532 to discuss your planned layout.

Drive-In & Drive-Through Rack

Drive-In Rack

Traditional pallet rack is a great solution for many warehouses, but if you have a lot of inventory that shifts on a regular basis, drive in or drive through rack is a storage solution you may want to consider. While traditional static rack storage allows for many rows of pallet racking with aisles between the individual rows, drive in and drive thru racking allows for a much denser arrangement of your stored product. Both drive-in and drive through rack systems allow more efficient use of available space than traditional multi-aisle selective racks systems. In fact, when compared to a conventional selective rack system, the same amount of storage can be acheived with a high density drive in or drive thru system in 80% less space.

High density storage racks work by utilizing standard pallet rack uprights in conjunction with rail beams or more simply, rails to store the pallet loads in a very dense configuration. The key difference between these racks and selective pallet racks is that the forklift truck operates inside of the rack itself and there are no specified lanes between the rows. The forklifts enter into the individual bays of the rack and the bays themselves can be as long or as short as needed.

Drive in rack and Drive through rack systems decrease storage and retrieval time while increasing efficiency and productivity among workers. Not only do they benefit your operations, they can also decrease your bottom line by giving you more storage room per dollar spent on racking. Because these racks create a more uniform load in a confined storage area, your forklift operators working in the system become more skillful drivers. In addition to these benefits, consider this - drive-in & drive-thru systems are very energy efficient. Since the product is so densly loaded in this type of system, there is less air to be heated or cooled between your pallets and your forklifts don't need to drive as far to pick or place loads thereby using less fuel.

Pallet Rack/Drive-In Rack Comparison

Clearly, Drive-in or Drive-Through is not for everybody however, it is exceptionally good at storing large quantities of palletized materials in a smaller space than would be afforded by selective pallet rack (see figure 6).

Drive-in Rack vs. Traditional Static Pallet Rack Layout - Shows Benefits of High Density Storage

Types of High-Density Storage Rack

Within the class of drive-in or drive-through racks are several notable configurations - most commonly defined by the length of storage time and ease of retrieval needed for the product being stored (see figure 7).


One Way Drive In - Last in First Out (LIFO)
Material is both stored and retrieved from the same side (entry point) in several aisles. For this reason, the first material put in this system is the last to come out. This works well where shelf life is at a minimum or not a major concern. This system also works well in cold storage environments or warehouse freezers.

Two-Way Drive In - Multi First-In Last Out System
Arranging drive-in to be enterable from two sides allows for maximum space usage and easy product accessability from two seperate sides.

Drive-Thru - First in First Out (FIFO)
Free access from both sides allows materials to be stored from one end and retrieved from the other. With this capability, a first in first out storage arrangement is made possible. This system is used where there is expiration dated material or wherever shelf life is of major concern.

Types of Drive-in & Drive-Through Rack


Pushback Rack

Push Back Rack

A push-back racking system can be a great option when you're tight on space. In a push back rack system, the pallets each sit in a tray that rides along rails in the rack frame itself. The push back rails are supported on an incline and gravity moves the trays along the rails towards the front of the rack. From the front, the loads are both picked and deposited while the back of the rack remains closed. When a load is deposited to the front of the rack, it will "push back" the previosuly placed load, thus decreasing picking times but keeping the number of picking faces to choose from high.

Pushback Rack Rails

Push-back racks can store multiple sized pallets up to six deep and four high making push-back rack a very efficient LIFO (last in, first out) system. This type of dynamic storage system allows you to have all the benefits of a high-density storage system without the drawbacks of a drive-in system. Let's look at this further.

With a typical high-density drive-in system, each bay will typically be filled same type of product. That way, when retrieving products one need only go to that 'pick-face' to get any one item. If dissimilar items were to be placed in the same bay that entire bay may potentially need to be unloaded to get at the needed product, thus wasting a large amount of time and resources. However, with a pushback system many different products can be placed in lanes within the same bay allowing for a larger quantity of pick faces. With each individual lane being a seperate product, those products will still be accessible without first unloading the rack.

Comparison of Push Back vs. Drive-In Rack - Pushback allows for more pick faces per bay.


Pallet Flow Rails

pallet flow rails - single & double pallet flow

Similar in concept to pushback rack is a pallet flow system. The pallets move from back to front and as they are removed from the rack, the next in line takes the previous pallet's place. Unlike pushback rack however, the rack is usually loaded from the back and picked from the front.

Almost any static pallet rack system can be retrofitted to be a more efficient dynamic storage system because the pallet flow rails drop into place using the existing racking components as their support structure. Lanes of pallet flor rails usually have built-in 'brakes' that work to slow the pallets to a smooth gentle pace as they glide down the lane. One of the biggest strengths of pallet flow rails over pushback is that flow rails will allow a longer lane. For example, while pushback may be able to store pallets 5 deep, a pallet flow system will allow as many as 10-15 pallets deep.



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