Archives for September 2018

Narrow Aisles and Very-Narrow Aisles in the Distribution Center: Space Saving Benefits and Equipment Requirements

By Ian Hobkirk | 09/19/2018 | 8:16 AM

Six Ways to Postpone DC Expansion Part III - Narrow Aisle - DCVThis blog is the third in a series on ways to optimize space in your distribution center to extend its ability to support growth and postpone a capital expansion project. So far, the blogs in this series have covered the concepts of slotting and optimizing storage depths. In this post, We’ll explore aisle widths and the pros and cons associated with the lift trucks that go along with a move to narrow (and narrower) aisles.


When expanding the footprint of the warehouse is not an option, companies often employ creative techniques such as using narrower aisles to improve space utilization. Given the potential for space savings, it can be tempting to redesign a distribution center to utilize this equipment, however, careful thought must go into the design to ensure an effective operation. Often the vehicle requirements are a deciding factor for companies evaluating a footprint that incorporates narrow or very-narrow aisles.


Narrow-aisle lift trucks have been in use since the 1950’s, but are still not used in some distribution centers that would benefit from their space-saving features. Conventional sit-down style lift trucks require aisle widths of 11 to 14 feet. Reach-style lift trucks only require 8.5 to 9.5-foot aisle widths and cost only slightly more than sit-down units. However, reach trucks cannot drive in and out of trailers. So, if true dock-to-stock operation is required, then companies should consider a compromise vehicle: the stand-up counterbalanced truck, which requires 10’ aisles. All of these lift truck types cost within approximately 15% of each other.


Very-narrow-aisle lift trucks are in a category of their own. These trucks can cost three to four times as much as a conventional lift truck, but they can operate in 5.5’ aisles and offer tremendous space savings. Of the two major categories of very-narrow-aisle trucks, “turret trucks” are generally regarded as the fastest. They can also double as a case picking vehicle for multi-level picking, as the operator rides up with the load. Conversely, swing mast trucks keep the driver on the ground, but are often better suited for maneuvering in tight areas. Since there are only a few inches of clearance between the lift truck and the pallet rack, very-narrow-aisle vehicles usually require rail guidance or wire guidance systems to prevent collisions.


The next blog in the series will describe ways you can get creative with unused space above your distribution center dock area to increase capacity. Can’t wait? Read the Whitepaper: Six Ways to Postpone -Or Avoid- DC Expansion or watch the recorded webinar.

How to Optimize Storage Depth to Create Space in Your Distribution Center

By Ian Hobkirk | 09/14/2018 | 4:40 AM

How to Optimize Storage Depth DCV Blog

This blog is the second in a series I’m writing on ways to optimize space in your distribution center to extend its ability to support growth and postpone a capital expansion project. I covered the concept of slotting as a space-saving strategy in the last post. In this blog, optimizing storage depth is the focus.

One of the largest areas of opportunity for many of companies lies in optimizing storage depth in the distribution center. Warehouses that have a significant number of SKUs where two-to-three pallets are regularly kept on hand should consider storing this product in a medium other than Single-Deep pallet rack.

Single-Deep rack sacrifices too much space to aisles to store large quantities of the same SKU in this medium. Instead, companies should consider allocating a certain percentage of their distribution center space, twenty percent for instance, to deep-lane storage mediums such as those listed below:


Push-Back Rack

Push-Back rack can be used to store pallets just two positions deep, or up to five positions, without sacrificing additional space to aisles. Pallets are loaded into the same side of the system from which they are picked. The company’s existing lift trucks can be used to access the rack, and each vertical level of storage can be used to store a different SKU. Drawbacks to Push-Back rack include its cost as well as the fact that FIFO (first-in/first-out) storage is not accommodated.  Image Source: Interlake Mecalux


Pallet-Flow Rack

Pallet-Flow rack, on the other hand, does allow FIFO storage. Pallets are fed into the back of the system and retrieved from the front, so more aisle space is required than for Push-Back rack. Storage depths can be much greater than with Push-Back rack (10-deep in some cases), and there is still no special lift truck requirement. Pallet-Flow rack is generally regarded as one of the most expensive ways to store pallets, however. Image Source: Interlake Mecalux




Double-Deep Rack

Double-Deep rack is much less expensive than Push-Back or Pallet-Flow rack, but special “deep-reach” lift trucks are required to access it, which can cost 10% to 20% more than normal reach-style lift trucks. Although pallets can only be stored two positions deep, Double-Deep rack is highly flexible. If designed with this idea in mind, Double-Deep rack can often be reconfigured as Single-Deep rack if requirements change in the future. Image Source: Aceally International



Drive-In Rack

Though relatively inexpensive, Drive-In rack is much more limiting than the three previous storage mediums.
Drive-In rack is often configured in depths of four to five pallets, but ALL of the vertical levels in a Drive-In system must contain the same SKU. Companies with frequent occurrences of ten or more pallets of the same product should consider this form of storage.  Image Source: Interlake Mecalux





In the next blog in this series, “Narrow Aisles and Very-Narrow Aisles in the Distribution Center: Space Saving Benefits and Equipment Requirements,” we’ll explore aisle widths and the pros on cons associated with the move to narrow (and narrower) aisles. Can’t wait? Read the Whitepaper: Six Ways to Postpone -Or Avoid- DC Expansion or watch the recorded webinar.

The opinions expressed herein are those solely of the participants, and do not necessarily represent the views of Agile Business Media, LLC., its properties or its employees.

About Ian Hobkirk

Ian Hobkirk

Ian Hobkirk is the founder and Managing Director of Commonwealth Supply Chain Advisors. Over his 20-year career, he has helped hundreds of companies reduce their distribution labor costs, improve space utilization, and meet their customer service objectives. He has formed supply chain consulting organizations for two different systems integration firms, and managed the supply chain execution practice at The AberdeenGroup, a leading technology analyst firm.


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