Making Sense of the Many Shapes, Styles, and Sizes of Pallets
Typically, pallet flow rack is designed to flow palletized inventory. Yes, there are times when pallet flow is used for non-palletized inventory, but the vast majority of systems are used with pallets. To that end, pallets become critical in the design specs for the pallet flow lane configuration. Mallard Best Practices is back with a comprehensive resource to help you understand the essential pallet specs and how they relate to your gravity flow system. Use this helpful guide for system design.
As you can see from the chart above pallets come in a number of styles and materials. Let’s review basic pallet terminology to be able to define the styles and apply it to pallet flow lane design.
Length: Refers to the length of the stringer.
Stringer: Sometimes referred to as runners, these are the board that runs the length of the pallet between the top and bottom deck boards (hold the pallet up). They are either a solid or notched beam to allow for forklift entry. Pallets can have from 2 – 5 stringers per pallet.
- A notched beam design creates a 4-way pallet. This is the most common.
- A skid is a pallet with no bottom decking. It is usually always a 2-way pallet.
*Pallets can have a rectangular, square, or cylindrical spacer between the top and bottom deck boards instead of the stringers. These pallets are called block pallets.
Deck boards: The boards that run perpendicular to the stringer and are mounted atop.
While we’ve already acknowledged the variety of pallet styles, there IS a “standard” pallet called a GMA-style pallet that is most common and actually the pallet most widely accepted in North America. There are value and benefit to using a pallet standard.
What Makes a Pallet “Standard”
GMA stands for the Grocery Manufacturer’s Association. This organization sets the standard that many people use and apply as the guideline for pallet manufacturing. Pallets that meet these guidelines are then often referred to as GMA-style pallets.
A universal pallet has many benefits. Importantly, it allows for pallet-handling equipment and automated systems to work across different industries and manufacturers with ease. To determine if a pallet is GMA-style it must conform to these parameters.
GMA-Style Pallet Parameters:
- Dimensions: 48” x 40” x 6 ½”
- Stringers: 1 3/8″ x 3 1/2″ x 48″
- Top and bottom deck boards are 5/8″ thick.
- Top of pallet has a 5 1/2″ x 40″ board on each end and five 3 1/2″ x 40″ boards in the center.
- Bottom of pallet has a 5 1/2″ x 40″ board on each end, and three 3 1/2″ x 40″ boards positioned between the notches.
- Alternate acceptable construction for GMA pallet is 6 5/8″ x 5 1/2″ x 40″ board on top, and four 5/8″ x 5 1/2″ x 40″ boards on the bottom.
- Other common pallet dimensions: 42 x 42 and 48 x 48
Now that you understand what a GMA-style pallet is, this is the process for determining if your pallet fits within that criteria.
Measuring & Orienting Your Pallet
To properly measure your pallet, the Mallard team put together a quick video tutorial. There are three main points to measuring your pallet correctly that apply to pallet flow lane design.
- Pallet width
- Pallet depth
- Direction of flow
As you can see in the video, we measured a plastic iGPS, and two wooden pallets –GMA-style and a CHEP (iGPS & CHEP are brand specific pallets). All three pallets measured 40”w x 48”d but they are all differently designed… which is important as we continue in our pallet flow lane design discussion.
Breaking down the video elements:
- Pallet width – refers to the direction of the deck boards. The width of a GMA-style pallet is going to be 40”.
- Pallet depth – refers to the direction of the stringers. The depth of a GMA-style pallet will be 48”.
- Direction of Flow (Pallet Orientation)
Pallet Orientation refers to the orientation of the stringers relative to the direction of flow.
At Mallard, we define pallet orientation as:
- The “easy” way(a.k.a. – right way) – bottom boards run parallel to the direction of flow
- The “hard” way(a.k.a. – wrong way) – bottom boards run perpendicular to the direction of flow
- Bi-directional– pallet can flow in either direction with max dimension dictating the direction of flow
GMA-style pallets are generally oriented “the hard way” (40”w x 48”d) resulting in the most efficient use of space if inventory requirements dictate additional lanes. They are also easy for forklift operators to remove from the lane.
Whereas, orienting the pallet “the easy way” (48”d x 40”w) allows more pallets per lane, but it does take up more horizontal space. Additionally, they are extremely difficult to extract because the fork pockets are too shallow to adequately remove without damaging the beams. Consider it as a solution for a lower number of SKUs but a larger quantity of each.
Pallet orientation must be established before configuring the pallet flow lane. Benefits to orienting the pallets “the hard way” can include more pallet flow lanes and easier forklift loading and unloading (due to the positioning of the fork openings on the pallet).
Designing Your Pallet Flow System to Your Pallet
Now that we know all about our pallets, here is how that knowledge applies to proper pallet flow lane configuration. Note: for successful flow projects the same pallet type and similar weight ranges will result in a successful flow project.
The goal of a pallet flow lane is controlled and consistent flow from the load (charge) side of the lane down to the pick (discharge) side. The pallet needs to flow at a safe pace and stay centered to arrive at the pick face squared with the lane and easily accessible for the forklift to remove. A poorly designed lane or an under-designed lane can result in pallets stuck in the lane which is inefficient and possibly dangerous. Taking the time to get the lane configuration right pays in the years of trouble-free use.
Key pallet specs to determine system design:
- Pallet type
- Pallet orientation
- Pallet dimension – depth x width
- Bottom description/surface space
- Pallet load weight range – min/med/avg/max
- System depth
- System width – # of Lanes
- Facility – layout/space/environment (climate)
As you can see, the first four key pallet specs have to do with the pallet specifically. It is that important to the pallet flow lane design. We’ve reviewed pallet types, pallet orientation, pallet dimensions… lastly, we will review the significance of the bottom configuration of the pallet.
Typically, the more bottom boards, the better the contact… the better the flow. Pallet flow rack can be designed to work around even sparsely manufactured pallets, you may just need to alter your pallet orientation, apply a pallet flow accessory, or make adjustments to help guide the pallet. In those cases, it’s best to consult the Mallard team for direction.
However, even with a standard number of bottom boards, the quality and thickness of the boards are also important. Good quality bottom boards… and by extension, good quality pallets will result in better pallet flow performance, fewer hang-ups, and minimized warehouse safety concerns and inventory damage. Pallets that are broken or splintered will track poorly down lane and could leave debris behind damaging the lane and causing pallets to get stuck. Hardwood boards are preferable vs soft (i.e. pine) which can conform to the pallet flow wheels or rollers under the load weight and obstruct the flow. Avoid downtime and potential inventory damage by retiring or repairing damaged and inferior pallets. Here’s a deeper look at what constitutes a good vs poor pallet for use in pallet flow.
Avoid These Damage Conditions:
- Missing boards
- Broken runners
- Inadequate / inferior fasteners
- Protruding or damaged nails
- Weak blocks or warped boards
- Dangling stretch wrap or other debris
The number and positioning of the bottom boards will also have an impact on whether wheeled or roller pallet flow would be best.
Wheeled vs Roller Pallet Flow
With the caveat that every Mallard pallet flow lane design project is application-driven, we can generalize a bit and note that we typically use full-roller pallet flow for applications using non-standard and plastic pallets. Non-standard would include plastic pallets, pod pallets, metal containers, corrugated containers, and slip pallets. Still, full roller remains the most adaptable.
Plastic Pallets are gaining in popularity and for good reason; they’re weather-resistant, reusable, sustainable, easy to clean, bug-free, and durable. While they are a great choice for many warehousing situations, they do have their limitations, cost being chief among them. When considering plastic pallets for your pallet flow system, consider these critical factors that can impact design and performance.
Plastic Pallet Challenges
- No standard design – with a wide variety of styles and configurations you’ll need to know your specs before designing your pallet flow system. For example, plastic pallets can have steel runners or protruding pod feet.
- Temperature-sensitive – heat will cause the physical properties to change in plastic pallets often resulting in conforming issues; the pallet can mold slightly to the pallet flow wheel or roller causing flow, restart, and hang-up issues.
- Load-weight sensitive – load weight can cause similar conformity or molding issues.
- Pallet surfing – the pallet bottom tends to skid over gravity flow rollers rather than make consistent contact due to design and uneven molding/construction.
Typically, roller pallet flow offers greater contact for plastic pallets, but they also have a greater tendency to “surf” over the galvanized rollers vs wood pallets. Lane pitch can help slow the pallet but Mallard also offers Ultra-Grip rollers to make better contact with the pallet and keep them flowing.
Special Note: One plastic pallet that doesn’t follow the general rule above is the iGPS plastic Gen 1 pallet. After considerable testing in the Mallard lab we’ve determined that the Gen 1 pallet flows better in a wheeled system like Magnum wheel pallet flow. The Next Gen iGPS pallet with its waffled pattern bottom flows well on full roller pallet flow.
Confirming Your Pallet Flow Lane Configuration
Testing the pallet flow lane prior to ordering is the perfect answer to ensuring the best system flow. The Mallard in-house testing lab is the go-to place. Testing gives you the opportunity to tweak the design and even change it if necessary before it’s too late. Call the Mallard team to go over your system needs and schedule a pallet flow test.