Laying Out Your Pallet Rack System for Maximum Efficiency
Methods for a more effective warehouse design
When you want to organize and optimize warehouse space, pallet racks are one of the best places to start, since racks occupy a large percentage of space in most warehouses. Good layouts let you optimize your facility, pick faster and store more. You can produce more, faster and safer.
#1: Longer rows can store more pallets in the same space
Because it maximizes the number of pallet positions and reduces the cost per position, you should usually layout your racks so that your rows are as long as possible in a given space. Because you can do starter/adder configurations, long runs also reduce the number of uprights in the system. Choppy, short layouts are more expensive and take up more space.
Example: A 100′ x 50′ space with 12′ aisles can store up to 480 pallets (given 22′ of clear ceiling height) in 60 bays if the racks run 100′ long. Flipping those racks in the same space to run the 50′ footprint will result in more starter frames, shorter “choppier” aisles, longer picking/putaway times for more pallet positions and fewer storage positions. Building columns and other obstructions will always play a role in the number of racks you can install in an area.
Space utilization may not be your top priority
But this isn’t a hard-and-fast rule because space efficiency isn’t the only factor. Vital functions like work cells, dock doors or staging areas will disrupt long, clean lines of racks, and that’s okay. If you have these areas that create shapes like “L” shapes, some racks may run long while others don’t, and that’s fine. Functionality may be more important than squeezing every last inch of space in many facilities.
#2: Use all your vertical space
Warehouses have tall ceilings that can often accommodate very tall racks that let you take pallets up, not out. If space is an issue, tall uprights let you use every foot of vertical area rather than more horizontal space. We’ve seen many storage operations that could fit at least one more layer of pallets at the top of the system, even allowing for clear ceiling height.
Very tall systems may pose some difficulties, but nothing you can’t overcome with the right equipment and training.
See more: How to Safely and Effectively Load & Unload Tall Pallet Racks
#3: Know everything possible about your facility
Ideally, you’ll start with an accurate CAD drawing. If you don’t have one, you should acquire one before you add racks (or anything else). Good drawings will include everything that can get in the way — fixed assets, HVAC ducts, building columns, work cells, doors, etc. Knowing where all these things are helps you understand the amount of space you have before you start the project. This information lets you know what you can and cannot change as you work on your facility.
Column locations and ceiling/wall obstructions are critical to good layouts. With those clearly marked, you can get a much better idea of how much rack your facility can take, and its overall strengths and weaknesses in terms of storage capacity.
See more: Measuring Your Facility, Part 2: Common Obstructions & Interferences
#4: Your layout starts with load factors
Deep understanding of your loads are where good design starts.
When rack projects fail, one of the most common reasons is that the rack wasn’t adequate for the load. This can be due to size, capacity or other factors. For instance, very compact, dense and heavy loads that do not rest on both beams and have to be supported by decking or supports between the beams mean that the rack’s capacity becomes the same as whatever those components can hold. The rack itself is fine, but the decking could fail. Knowing what’s going on the rack today (what it is, what it weighs) is critical. It’s also important to project what may be stored in the future if possible.
Also, load sizes play a big part in space planning. For instance, we’ve seen facilities where simply reducing the beam width allowed more pallet storage. Knowing that your current and future loads can be stored on a certain beam size lets you design more efficient layouts.
#5: Place the “A” products in your best locations
This is product slotting 101: place the pallets you’ll use most often in your most accessible places, where forklifts and people will travel the least distances to access them. Most operations follow the Pareto pattern — 20% of inventory generates 80% of the volume. Whatever the case in your operation, you should make sure your fastest moving items can be put away and picked with the least effort.
At times, this mix will change, and you’ll have to reevaluate your storage strategies.
#6: Mix static and dynamic storage
Placing a cell of pallet flow in the right area saves tons of space and makes picking and placing easier, assuming your product is something that can work within the accessibility limitations of pallet flow (it’s a first-in, first out system for single SKUs in a bay). Successful storage strategies often hinge on flexibility, so a cell of pallet flow or pushback rack combined with a selective rack warehouse is perfect for many operations.
See more: Selectivity vs. Storage Density
Steps to maximize your pallet rack layout
- Use longer rack rows rather than shorter, choppy ones wherever possible. This gives you more pallets in the same space.
- Maximize vertical space, which can add many new pallet positions in the same space.
- Understand all your facility factors. Accurate and updated AutoCad drawings are invaluable.
- Your layout should start with understanding load factors.
- Slot your pallet storage so that the most popular pallets are the easiest to access.
- Mix dynamic (flow, push-back, drive-in) and selective racks when you need a blend of storage density and accessibility.
More resources
- How to Measure and Improve Industrial Storage Space Efficiency
- Finding New Space in Your Facility
- Case Study: Zero Mountain Adds Frozen Storage in Unfriendly Terrain
Scott Stone is Cisco-Eagle's Vice President of Marketing with 35 years of experience in material handling, warehousing and industrial operations. His work is published in multiple industry journals an websites on a variety of warehousing topics. He writes about automation, warehousing, safety, manufacturing and other areas of concern for industrial operations and those who operate them.