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Industry experts agree that selective racking is the most common type of pallet racking. It’s relatively simple in form and versatile enough to be used across a variety of storage applications. The main components of selective pallet rack are columns and struts fixed together to create the upright and shelf beams that connect the uprights to form the pallet rack bay.
Upright height is largely based on the amount of available warehouse space (ceiling height) and inventory volume (# of levels/bays). But one design feature that deserves some extra thought is the upright frame depth – did you know there were options for accommodating standard 48” x 40” pallets? In case you didn’t, we’ll help walk you through the variables….
Rack frame depth can be 42” or 48” deep for storage applications using standard-sized pallets. Both depths have pluses and maybe challenges depending on how you look at it.
Note: If you’re using odd-sized pallets, the Apex team can help you design a custom pallet rack configuration to accommodate the pallet dimensions.
The common formula to determine upright depth for standard pallets is to subtract 6” from the pallet depth. Example: Using a standard 48” long x 40” wide GMA-style pallet:
Subtract (48” – 6″) = 42″ deep uprights
As you can see on the image to the right, the 42” depth will allow 3” of pallet overhang in the front and back of the rack. Both front and rear pallet overhang must be accounted for in terms of determining aisle depth (front overhang) and proper adherence to fire safety requirements (rear overhang).
Note, however, that a minimum of 6” of open space is required behind the rack row. This open space is called a flue space, and it is a standard fire safety regulation. Therefore, if you are designing a system with two selective rack rows in a back-to-back configuration, the minimum flue space would be 12” or 2 x 6”. With the shallower 42” deep rack, the challenge for fork truck operators is to make sure the pallet overhang does not exceed the expected allotment and crowd the flue space.
Height-to-Depth Considerations
Pallet rack frames that are 42″ deep and taller than 20’ will exceed the recommended 6:1 height-to-depth ratio and may require additional engineering, i.e. special anchors, base plates, or overhead pallet rack ties. The Apex design team and provide specific project recommendations.
The other option would be to design the upright to the full pallet depth of 48”. Obviously, this would require more steel and, therefore, increase the cost of the system, but there are several advantages that might outweigh the additional cost.
Using a 48” deep upright with a 48” deep pallet allows little to no room for error in terms of forklift loading. The beams are spaced precisely to support both the front and rear of the pallet, so the responsibility is on the forklift operator to accurately place the pallet. Pallet supports and/or wire mesh deck can be added as an extra measure of safety to help support the pallet boards and help temporarily hold the pallet should the operator not initially catch both front and rear beams squarely. The pallet would have to be replaced so the load is on both the front and rear beams.
Neither pallet supports, nor standard deck is meant to hold the full weight of the pallet.
Choosing between the two upright depths will not affect the system layout. The 6” difference is made up in the flue space between the two racks in a back-to-back scenario by reducing the spacing from 12” to 6”, or not at all in a single-deep system as the aisle would be designed to accommodate the pallet depth either way.
We hope this blog answered a few questions regarding selective pallet rack depth design considerations. If you’d like additional information or system design support, our experienced pallet rack engineers are here to help – give us a call today, and we’ll get right on it!
This is your ultimate guide to maximizing your warehouse racking layout.
So if you’re wondering how to get the most out of your facility’s space, you’re in the right place.
In this article, you’ll learn:
Let’s dive in!
What is Pallet Racking?
Pallet racking systems are a storage method that leverages vertical space to store products and materials, whether single items or palletized loads.
Operators typically use forklifts to place and retrieve pallets and other materials stored on the shelves.
Pallet racking as a storage solution is extremely popular.
According to Frank Ceriello, vice president of sales for Aigner Index, some 80% of all industrial materials are stored on pallet racking.
What are the Different Pallet Rack Parts?
There are several pallet racking components that compose the shelving:
Let’s go through each one.
These are the vertical steel posts that connect to the horizontal beams and bear the downward weight on the shelves.
Beams mount horizontally to the upright frames – one in front and one in back – and compose the shelves.
There are two different pallet rack beam types:
Braces are the horizontal and diagonal bars, generally welded to the uprights, that support the uprights and provide extra strength.
Also called footplates or footpads, baseplates connect the upright frame to the floor and are secured with anchor bolts.
Also called support bars, crossbars are placed between the horizontal beams to support pallets or materials and prevent them from falling through.
Also called universal safety drop pins, beam locks, or beam connector locks, pallet rack clips are small fasteners used to secure the horizontal beams to the uprights.
They prevent the horizontal beams from dislodging during loading and unloading.
What are the Benefits of Pallet Racking?
Pallet racking leverages the vertical space in your facility, allowing you to store more products and materials without expanding your horizontal footprint.
Overall, it’s a lot like the advantage of building a skyscraper instead of a regular building.
Thus, the benefits of pallet racking include:
While many facilities use pallet racking, it may not be necessary for certain applications.
For instance, many beverage warehouses use floor stacking (also called “block stacking”).
In this method, pallets are simply stacked on the floor in rows.
This system can be arranged to provide extremely high-density storage if the pallets or loads can be stacked directly on top of each other.
Generally, floor stacking works best for Last-In, First-Out (LIFO) inventory management.
In a Last-In, First-Out (LIFO) inventory system, the first products or materials added are the last to be sold.
This method is less popular than FIFO.
In fact, the United States is the only country that allows companies to use this system.
Industries that use LIFO are typically those that sell commodities like bricks and stone since these materials are taken off the top of the pile and sold before the oldest materials are.
If this storage method doesn’t suit your needs, keep reading.
We’ll cover the other types of racking in the next section.
Pallet Racking Types ExplainedOverall, racking systems belong to two categories: low-density and high-density.
The advantage of low-density systems is that they afford better selectivity.
And the opposite is true of high-density systems.
Selectivity is how easily accessible products or materials are.
Certain types of warehouse racking layouts offer easy access (i.e. high selectivity) while others don’t allow order pickers to access products and materials as easily (i.e. low selectivity).
Density indicates the amount of goods or materials stored within a warehouse storage space space.
Different types of warehouse racking layouts will allow you to store more material (i.e. higher density) or less material (i.e. lower density).
High-density racking systems include:
Density and selectivity are related: The higher the density of storage, the lower the selectivity.
That said, let’s go through the common types of racking, their advantages and disadvantages, and common industries they’re used in.
Selective racking is the most common type of pallet racking.
And it works with any type of forklift, so no specialized lift trucks are required.
There are two types of selective racking: one-pallet deep and double-reach racking.
We’ll cover each separately.
Selective racking stores pallets one deep.
This system provides unobstructed access to each pallet within the system, making it ideal for the First-In, First-Out inventory systems.
First-In, First-Out (FIFO) is an inventory and accounting method wherein the first products stored are also the first to go out.
Overall, it’s the most popular inventory method used in warehousing.
Not only is it logical and simple, but it also works particularly well with perishable goods and other products that are subject to expiration or obsolescence.
Industries that often use FIFO include:
Selective racking is well-suited to applications with low inventory turnover along with high product differentiation.
Watch this video to see how one-deep selective racking systems work:
Double-reach – also called double deep – racking systems are very similar to selective racking.
But instead of using one row, racking is placed two rows deep.
Racking could even be placed both back-to-back and two rows deep on each side, therefore maximizing density.
This system offers more pallet positions by reducing the number of aisles.
But it’s only compatible with First-In, Last-Out inventory systems.
Overall, double-reach racking is well suited for applications with multiples of the same stock.
Watch this video to see how double-deep selective racking systems work:
With drive-in or drive-through racking, pallets are stored on rails in place of shelf beams.
These rails extend the length of the rack and allow forklifts to drive into the racking structure for pallet placement and removal.
Drive-in racking is ideal for storing a limited number of SKUs with uniform pallet sizes and load measurements.
This allows for consistent load rail heights.
These racking systems work best with Last-In, First-Out inventory systems.
Watch this video to see how drive-in/drive-through racking systems work:
Push-back racking consists of a series of nested, mobile carts which glide on rails.
The pallets are placed on the carts and stored in bays two to six pallets deep.
When a new pallet is loaded onto a cart, it pushes the other carts back.
It’s much like soft drink coolers in restaurants, grocery stores, and gas stations.
As you pull a soda bottle out, a new one slides forward.
Push-back racking works best if you have little storage space and products that are consistent in size and weight.
This system is ideal for Last-In, First-Out (LIFO) inventory systems.
Watch this video to see how push-back racking systems work:
Pallet flow allows up to 20 pallets to flow down an incline on a series of rollers or wheels.
The pallets are loaded on one end of the system and unloaded at the other end, making it optimal for First-In, First-Out inventory management.
This system is an excellent option for applications with a very limited number of SKUs in large volumes.
It also works well for perishable or time-sensitive products.
Watch this video to see how pallet flow racking systems work:
This type of racking consists of protruding arms and is designed to hold lengthy materials, like pipes and wood.
Because the racking isn’t obstructed by solid vertical uprights, cantilever racking is well-suited for awkward or oversized materials.
This system is ideal for Last-In, First-Out (LIFO) inventory systems.
Watch this video to see how cantilever racking systems work:
We’ve compiled this quick pallet rack comparison chart to help you decide which option works best for you and your facility.
Racking Type Ideal For: Specialty Equipment Required Storage Density Inventory Management System Cost Selective Products of any volume, weight or size No Low FIFO $ Double-Reach Multiples of the same stock Yes Medium LIFO $ Drive-In Limited number of SKUs with uniform measurements No Medium LIFO $$ Push-Back Products consistent in size and weight No High LIFO $$$ Pallet Flow Very limited number of SKUs in large volumes No High FIFO $$$ Cantilever Oversized and awkward products No High LIFO $ How to Choose the Best Type of Pallet Racking for Your NeedsThere are several important factors to consider when selecting pallet racking types.
Let’s go through each one.
Each type of pallet racking will cost a different amount.
So you’ll need to consider the cost per pallet of the system you desire.
We’ll cover the cost of warehouse racking in a later section.
How much room does your facility have?
Certain racking systems take up more room than others.
So you’ll want to be sure you select a system that’ll fit in your facility.
We’ll cover the steps to do that in the next section.
Some types of pallet racking require specialized material handling equipment.
For example, to be compatible with drive-in/drive-through racking, lift trucks require a special overhead guard.
Additionally, if you plan to use narrow aisles, you’ll need a forklift with a small footprint for maximum maneuverability.
If you plan to handle a large variety of materials and products, your racking will need to be able to accommodate them.
As we’ve noted, certain pallet racks are better suited for FIFO and LIFO inventory management systems.
If you want to learn more, please visit our website Heavy-Duty Crossbeam Rack.
So whichever method you use, you’ll need to make sure your pallet racking can accommodate it.
A Step-By-Step Pallet Rack Design GuideWhen designing a pallet racking system, the goal is to fit as much material into the available space as possible while still allowing for enough room to quickly and easily retrieve items.
With that said, let’s go through how to determine the pallet racking layout for your facility.
This will help you get clear on exactly how much square footage you have available to work with.
Obstacles can include things like columns, doors, and mezzanines – anything that you’ll need to make space for.
Fast-moving products should be placed near your shipping lanes so that it takes less time to retrieve and ship them. If you’re storing production materials, you’ll likely want to put them closest to your production line to cut down on pick times.
Take the largest pallet you handle, and measure the height (load plus pallet height), depth, width, and weight. These measurements will tell you how much space you’ll need to accommodate your products and materials for storage.
According to Speed Rack West, the most popular pallet rack frame depths are 42-inch, 48-inch, and 36-inch.But keep in mind that you’ll need 3 inches of overhang on each end of the pallet. So to factor that in, simply subtract 6 inches from the depth of your pallets. For example, if your pallets are 48 inches deep, you’ll need a 42-inch deep pallet rack frame.
Per Stein Service Supply, pallet racking beam sizes are generally 4-feet, 8-feet, 9-feet,10-feet, or 12-feet.You’ll use the width of your pallets and how many you plan to store side-by-side to make this determination. Just keep in mind that you’ll need 3 inches of space between the frames and the pallet, and 4 inches between each pallet. For example, if you have 40 inches pallets and you want to store two pallets per shelf, you’ll need beams at least 90 inches long. You’ll also need to consider the capacity of the beams you choose. The capacity is determined by the size of the beam face, in addition to the length. The taller the face, the more weight the beam can handle. Conversely, the longer the beam and the shorter the beam face height, the less capacity the beam can safely handle. You can reference this general beam load capacity chart as you do your calculations (capacities are per beam pair):
Beam Length 3-Inch Beam Height 4-Inch Beam Height 5-Inch Beam Height 6-Inch Beam Height 96 Inches (8 Feet) 2,000 lbs. 4,000 lbs. 6,500 lbs. 8,000 lbs. 108 Inches (9 Feet) 1,500 lbs. 3,000 lbs. 5,500 lbs. 7,500 lbs. 120 Inches (10 Feet) 1,200 lbs. 2,500 lbs. 4,500 lbs. 7,000 lbs. 144 Inches (12 Feet) 800 lbs. 1,800 lbs. 3,000 lbs. 5,000 lbs.This chart is only meant to serve as a basic reference. Beam capacities vary depending on the manufacturer, beam gauge, and various other factors. Consult with a warehouse racking layout professional for specific capacities.
The standard sizes for pallet racking uprights are 8-feet, 10-feet, 12-feet, 16-feet, and 20-feet.To find the right size, you’ll need the your pallet load height, pallet height, number of pallets stored high, beam height, and beam-load clearance (at least 3 inches is recommended – all measurements should be in inches).Once you have this data, you can use this Excel-based calculator to automatically generate the upright height for you. Just click below to download it: Upright Frame Height Calculator Keep in mind you’ll also need to leave 18 to 24 inches of space between the ceiling and the top of your highest pallet, to conform to fire codes. Once you have your height, be sure to take into account the maximum lift height of your forklift. That way, you can ensure you’ll be able to access the materials at whatever height you choose. Once you’ve put all this information together, you’ll have the pallet rack dimensions you’ll need to accommodate your products and materials.
Once you have your pallet racking dimensions, you’ll want to consider your aisle widths.
That way, you can maximize your existing storage capacity.
Typically, warehouse aisles are broken into the following three categories:
Let’s go through each one below.
Your average sit-down, counterbalance forklift will utilize wide aisles, which are 10.5-feet to 13-feet wide.
That means you won’t need to invest in specialty equipment.
With wide aisles, however, much of the available space is devoted to the aisles rather than the racking.
So it’s the least optimal aisle width for maximizing storage capacity.
At 8.5-feet to 10.5-feet wide, narrow aisles allow you to pack more products into your facility.
But they require equipment with a tight turn radius to avoid hitting the racking.
Three-wheel forklifts have a tighter turning radius and would be able to work in narrow aisles.
Order pickers and reach trucks are other options for narrow aisle operation.
Overall, users of narrow aisle configurations can realize a 10 to 15% percent gain in storage space over wide aisles.
At 5-feet to 7-feet wide, very narrow aisles give you the ability to greatly increase capacity without expanding the footprint of your facility.
But, you’ll need to take into account the added costs of very narrow aisle forklifts, if you don’t have any in your fleet.
Training your team members on the new equipment will incur additional costs as well.
Overall, very narrow aisles can allow you gains of 25% to 35% over wide aisles.
Choosing your aisle widths is a balancing act.
You want to achieve the optimal storage utilization for your facility, which is between 80 to 85% of your filled floor space.
But you also need to allow enough room to safely and efficiently pick and place products.
Fortunately, you can easily calculate the minimum aisle width for your facility.
Just use this simple equation:
Don’t forget to use the same unit of measurement for all areas of the formula.
Take a look at the example below:
In this example, you end up with a 142-inch minimum aisle width.
Or almost a 12-foot aisle.
This would be a regular aisle width (not narrow or very narrow).
Now that you have all the information needed for your warehouse layout, your racking dimensions, and your aisle widths, let’s talk about the cost of installing pallet racking.
Pallet Rack Prices: What You Can Expect to PayWhen it comes to the cost of warehouse racking, the rule of thumb is the higher the storage density, the higher the cost.
So selective racking – since it offers less density – will cost less than pallet flow racking, for example.
Drawing from TranSystems’ Rules of Thumb: Warehousing & Distribution Guidelines, here are the prices you can expect to pay for warehouse racking:
Pallet racking is prone to daily damage and abuse.
And while they’re built to handle heavy loads, that strength has its limits.
Before we get into the nitty-gritty of pallet racking safety, let’s first cover what the Occupational Health and Safety Administration (OSHA) has to say on the topic.
Unfortunately, OSHA does give exact guidelines for pallet racking safety.
What they do say on the topic is confined to two standards: 1910.176 and 1910.159.
These standards say that:
Beyond that, OSHA’s guidance for pallet racking falls under the “General Duty Clause Section 5(a)(1)“, which states that:
“Each employer shall furnish to each of his employees employment and a place of employment which are free from recognized hazards that are causing or are likely to cause death or serious physical harm to his employees”
While OSHA may not give much in the way of specific pallet racking guidelines, failure to adhere to what they do dictate is a serious matter.
So let’s cover some common OSHA warehouse racking violations.
Overall, OSHA tends to issue pallet racking violations to employers for:
Although OSHA doesn’t give much in the way of specific guidelines for warehouse racking layouts, the American National Standards Institute (ANSI) does.
Their guidelines are contained within the “Specification for the Design, Testing and Utilization of Industrial Steel Storage Racks” standard.
And they are the industry-adopted guidelines for pallet racking design and safety.
Please be aware, however, that this document doesn’t apply to all warehouse racking layouts.
Per the abstract:
“The standard applies to industrial pallet racks, movable shelf racks, and stacker racks made of cold-formed or hot-rolled steel structural members. It does not apply to other types of racks, such as drive-in or drive-through racks, cantilever racks, portable racks, etc. or to racks made of material other than steel.”
In it, you’ll find specific information on subjects like:
For more information, please refer to the free PDF copy linked above.
Note: This PDF was last updated in October 2012.
Please check ANSI’s official website as a newer version may be available.
To ensure your pallet racking is as safe as possible, you must perform regular inspections.
But what counts as “regular”?
Answer: It’s up to the owner’s discretion.
That said, a good rule of thumb is to do them either weekly or monthly, depending on your usage.
These inspections should be performed by someone familiar with the racking systems installed and the installation requirements.
And the results of each inspection should be kept on file in case it’s necessary to reference them in the future.
Overall, there are four items to check while inspecting your pallet racking:
Let’s go through each one.
Plumb and straight refers to the vertical trueness and degree of twist or bend that a pallet racking upright beam may experience between its centerline at the top and at the floor anchor.
The ANSI pallet racking guidelines we discussed in the last section give the maximum plumb and straight ratio:
The rack height (in inches) divided by 240
For example, if your racking is 12 feet tall (144 inches), the maximum plumb ratio is about 7 inches.
If any uprights exceed that limit, the racking must be unloaded and the problem component repaired or replaced.
Rust and corrosion can be detrimental to the structural integrity of pallet racking.
It can be an especially big problem if your racking is in a corrosive or moist environment.
Thus, it’s important to inspect your racking for rust and repair or replace any excessively corroded components.
Overloading a pallet rack can result in the beams bending and the safety of the racking being compromised.
To help guard against this, each beam in the system should be labeled with the maximum capacity for the shelf.
That way, operators will know at a glance whether the racking can handle the load they intend to place on it.
Indicators of damage can include:
If damage is found, the racking should be unloaded and the problem component either repaired or replaced (according to engineering specifications).
Download our free pallet racking inspection checklist to help you as you perform them.
Generally, yes.
In many cases, pallet racking is treated like any other building structure.
Thus, local building codes will apply and a permit will be required for installing pallet racking.
The ANSI guidelines from the previous section state that pallet racks should have anchors on every footplate to resist force.
You can read more about the specifics of that rule on pages 3 and 29-31.
It’s always best to consult an engineer and local building codes to determine exactly what’s required for installing pallet racking in your facility.
How to Prevent Damage to Your Pallet RackingOnce you’ve narrowed down the ideal racking for your warehouse, the last thing you want to see is damage.
Most racking damage is caused by overloading, inadequately engineered systems, or incidents with forklifts.
These issues can cause the center of gravity to shift away from the rack column at the base plate.
This offset causes the column to bend, which creates horizontal force and pushes the column toward the load center.
This cycle – called micro-shifting – continues until the racking structure becomes so unstable that a relatively minor impact can cause a major collapse.
So, what can you do to help prevent damage and possible collapse of your warehouse racking layout?
Let’s go through your options.
To combat damage to your racking and micro-shifting, you can add additional layers of protection to your racking system.
These include:
This can include adding lights and installing mirrors near the racking and on the lift trucks.
You already know that you must install capacity placards on your pallet racking to guard against overloading.
And while pallet racking is designed to carry lots of weight, it’s still good practice to place heavier items on the lower level of your racking if you can.
One of the major ways to prevent forklift operators from damaging your racking is training.
Operators should be familiar with the specific lift truck they’ll operate.
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And they should also understand the procedures for working effectively with and around the kind of pallet racking you use.
If impacts are an issue in your facility, consider lowering the speed limit for your material handling equipment.
Posting the speed limit where operators will see it can help reduce impact damage.
But if posted speed limits aren’t working, consider setting the speed control on your lift truck – if it’s equipped – to electronically limit the maximum travel speed.
Your local forklift dealership should be able to help you do this.
ConclusionThere you have it: the complete guide to warehouse racking.
Now we’d like to turn it over to you.
What kind of warehouse racking does your facility use?
Or are you still deciding what the best option is for a new installation?
For more information, please visit mold rack.