In the continual endeavor to save money when it comes to pallets, less can be more. According to research by the Sardo Pallet Lab at Virginia Tech, shaving an inch off the height of a pallet translates into cost savings throughout the supply chain.
For years, researchers at the Pallet Lab have studied ways to improve efficiency, performance and cut cost by tweaking pallet design. The Pallet Lab’s latest discovery would require the pallet and some materials handling equipment, especially lift trucks, to be changed. But if everyone bought into the vision, companies could save a fortune according to Dr. Marshall Mark) White, the lab’s director.
Let’s look at the basics. Researchers measure the height of a pallet by adding the thickness of the deck boards and stringer for a stringer pallet and the deck boards, stringer board and block for a block pallet. The minimum vertical opening required for easy access by lifting devices primarily determines the pallet height. Other key factors for minimum vertical opening are pallet strength, stiffness requirements and common dimension of wood raw materials.
Today, many pallets in the United States are 4.75 to 5.5 inches high with the vertical opening between the deck boards measuring 3.5 to 3.75 inches high. Most standard GMAs and CHEP pallets have a vertical opening of 3.5 inches (89mm).
Pallet height has become a topic of discussion as the International Standards Organization (ISO) has met to develop a basic standard for pallet dimensions and tolerances used in international transit. The ISO committee responsible for the pallet standard (ISO 6780-1988) met in October and approved a standard calling for a minimum vertical clearance of 3.5 inches (89mm). The U.S. and Japanese delegations wanted 3.35 inches (85mm) while the Europeans called for 3.75 inches (95mm). All sides gave a little, and the committee eventually settled on the 3.5 inches (89mm) height. The Industrial Truck Association (ITA), the organization representing industrial track manufacturers around the world, opposed the height. ITA claimed the lower profile caused safety and functionality issues by making it harder for hand trucks to freely enter and exit a pallet.
Although it is true that a larger opening can make it easier for forked equipment to enter, having adequate clearance has not been a problem for the GMAs or the CHEP pallets, which tend to have the smaller openings, according to Mark. The smaller vertical opening only creates a problem for hand trucks not forklifts. Thus, hand trucks would have to be altered to accommodate the low profile pallet if the minimum vertical clearance dropped below 3.5 inches (89mm).
Why go to the effort? Virginia Tech’s research points to many reasons. A lower profile pallet would result in cost savings, increased space utilization in trucks, reduction in the weight of a pallet and conservation of natural resources. “You can reduce pallet price without affecting the functionality of a pallet by switching to a lower profile design,” said Mark. Most typical 2×4 pieces of lumber in the United States are 3.5 inches (89mm) in height. A special size has to be cut to satisfy the height requirement of a 3.75 inches (95mm) vertical clearance design. But a typical 2×4 can be used for the 3.5 inches (89 mm) vertical clearance design.
The difference between a 3.75 inches (95mm) and 3.5 inches (89mm) vertical clearance adds an extra 1.875 pounds of fiber for each 48×40 inches green hardwood pallet according to the Pallet Lab. For the 400 million new wood pallets produced per year in the United States, an additional 375,000 green tons of wood fiber are required to manufacture and recycle if all the pallets used the 3.75 inches (95mm) vertical clearance profile.
Possible space savings make the change attractive too. For an average case or sack height of 10 inches, the taller pallet profile causes a loss of up to one layer of product per pallet, or a 9% reduction of product volume in trailers, which cube out. This translates into increases in transportation fuel consumption, currently estimated at 18 billion gallons/year of diesel in the United States. Depending on the material handling environment and packaging, using a lower profile pallet could improve space utilization while substantially saving on fuel consumption.
Just consider what would happen if instead of shaving a quarter of an inch off the pallet, you cut a full inch off the height. Mark said, “The extra inch could be the difference between putting an additional layer of product on top of the pallet or not.”
The idea of a low profile pallet is not new. It has been used in the shingle industry for years. Using lower profile pallets in most traditional applications would require significant changes. To achieve Mark’s dream, hand trucks would need to be designed 2.5 inches high or lower instead of the typical 3.25 inches high. Current hand trucks would need to be replaced, which creates a tremendous business opportunity for industrial truck manufacturers to sell more units. Less wood in the pallet would require a reduction in rack spans. Some might think these are drastic measures just to trim an inch. But according to Mark, the supply chain savings and improvement in material handling efficiency will more than offset the costs. Besides, he pointed out that many facilities are already retrofitting racks for safety reasons. Companies are putting new shelving and bracing in every day. When a facility buys new racking systems, all it would need to consider is reducing spans by a couple of inches.
Just because the concept makes sense on paper to researchers, don’t expect to see it on the market any time soon. The technical staff at the ITA has not warmed up to the idea. Change always takes time. Packaging users would have to push the idea. Mark estimates that it will take 5-10 years if not longer to see his dream become a reality. The idea of a lower profile gives you something to think about when it comes to what the best overall pallet design for the future.
Should wood pallet manufacturers and recyclers oppose the idea of a low profile pallet? Although it would likely lower the cost of the pallet, the design would use less wood too. Thus, the design change would not necessarily impact the profits of pallet companies. Less wood utilized by the pallet industry would impact the low-grade lumber market in the long run. With pallets being the second biggest user of lumber in the United States behind home construction, the lower profile design would impact sawmills more than pallet companies.
Neither pallet companies nor sawmills may have much of a say in the end. “Ultimately, the customer is going to buy what is the lowest cost to them,” Mark said. “The 20th century pallet is five inches high; the 21st century pallet should be three inches high. The cost savings will be tremendous.”
Low Cost Ways to Improve the Performance of Wood Pallets
Poor pallet design can result in product damage, pallet failure, personal injury or in rare cases even death. According to Dr. Marshall (Mark) White of the Sardo Pallet Lab at Virginia Tech, 77% of all damage to wood pallet deckboards occurs at the top end deck boards. When forklifts impact the edges of pallets, the nails bend. They continue to bend in the deckboard until they literally split the deckboard at which time the heads pull through and the deckboard and or joint comes apart. Studies have shown that forklifts cause most pallet damage during materials handling.
Stiffness in the edge of a pallet is important. A stiffer edge deckboard results in higher impact forces. Thus, lower stiffness end boards such as plastic end boards are significantly more durable and resistant to impacts according to Mark. The center connections absorb most of the force (up to 50 percent). The ends absorb 25% on each end. Since the center joint carries 50% of the load, putting a stiffer nail and/or more nails on the center joint would result in more performance bang for the buck.
Moving the outside stringers in a little — creating a wing pallet — strengthens the outer joints and improves load distribution. This takes stress off the center joint, which can reduce splitting in the end joints. Keep in mind that wing pallets are not suitable for every application. Wing pallets cause problems for sacked product or situations where the pallet can get hung up in close quarters handling.
VA Tech’s research shows that if a company is constructing multiple use pallets, one of the most efficient ways to improve value is to add an extra nail to each of the connections in the end boards. Other methods include: putting denser species such as oak or plastic lumber on the top end deckboards. CHEP is testing plastic lumber now in its pallet pool. Other options include using stiffer fasteners (such as hardened steel) or butting end deckboards.
“The best way to improve the value of a wood pallet is to focus on the end board connections,” said Mark. Examining the results of the study, it appears in limited use or expendable pallets manufacturers can use fasteners, which are a bit lower in quality, that those that meet the criteria for the uniformed standard as now published by the industry. Mark’s research indicates that these lower quality fasteners may be used in hardwoods but are not usable in softwoods.
For more information visit www.www.palletlab.vt.edu.
