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Article | November 11, 2013
Stringer pallets vs. block pallets
The dominance of wood pallets continues as the two styles battle.
Even as other materials struggle to mount a credible challenge, wood maintains its stranglehold (90% or higher) on the worldwide demand for pallets. It’s a given that for the overwhelming majority of brandowners, the choice of material is, indeed, a given; therefore, a logical first decision is what type of wood pallet. There are various styles of decks; nonetheless, wood pallets are more commonly named for their bases. Within that classification there are two: the stringer pallet and the block pallet. A stringer pallet is so named because of the three “stringer boards” that form its base, and the even more self-defining block pallet derives its name from the blocks (typically 9) that form its base. There’s a deceiving simplicity to choosing a pallet, belying the complexities of the many consequences that stem from the choice. Costs and efficiencies are affected throughout the supply chain, specifically in material handling, transportation, and storage. Included within that scope is protection not only of product but of people, too. After all, a compromised pallet can lead so easily to injuries.Before delving into a discussion of the differences between the two pallets, it’s helpful to start with what they have in common in terms of performance requirements. Pallets must bear the weights of their loads; therefore, pallets need to have the requisite strength. Loaded pallets frequently are suspended between the rails of conveyors, on the forks of lift trucks, or otherwise exposed to conditions that can cause those pallets to flex; therefore, pallets need to have the requisite stiffness. Pallets typically take a beating from the physical forces (shock, compression, and vibration) that are ever-present within a supply chain; therefore, pallets need to have the requisite durability. The preceding list is not necessarily collectively exhaustive; however, no matter how much it might be extended, all of its items affect the requirement that pallets need to be cost-effective. A pallet’s strength, stiffness, durability, and other performance characteristics are reflected in the price, with cost-effectiveness being a function of trade-offs among the characteristics. Trade-offs are at the core of the systems approach, which, in turn, is only as reliable as the degree to which its inputs reflect company-specific circumstances.
Doing it the right way
Stringer pallets inherently are 2-way platforms, meaning they can be fork-handled from opposing ends at the width dimension. The disadvantages that such a limitation can impose on material handling are easily imagined; however, other activities also can be disadvantaged. The loading of transportation vehicles (trucks, especially) for best space utilization necessitates the placement of pallets lengthwise across, not withstanding that the practice of pinwheeling calls for alternating the pallets lengthwise and widthwise, in an interlocking pattern. And the safest and most convenient placement of pallets in storage racks is length-facing-the-aisle. Stringer pallets are made 4-way by notching, that is, by cutting out two areas in the stringer boards for fork insertion. By contrast, block pallets are 4-way by design.
Who’s yanking your chain?
A supply chain member with power and influence can exert them in decisions about pallets. Unlike times past, the muscular member is not always the brandowner. There’s no better example than today’s mega-retailers. Costco and Walmart have communicated their preferences for block pallets, and brandowners—in their self-interest—have complied. The two retailers have decided that block pallets are a better complement to store operations (the handling and displaying of products).
It’s a small world
A brandowner’s manufacturing, marketing, and logistics bear mightily on whether the proper choice is stringer or block—in other words, the issue is about how much of the world a brandowner’s operations cover. In the United States, the stringer dominates (despite the aforementioned preferences of big-box stores), perhaps, in part, because the stringer is the older kid on the block. Then again, an undeniable trend in industry is to think globally; therefore, knowledge of which pallets are preferred elsewhere in the world is essential. In Europe, Asia, Central America, and South America, the block pallet dominates. And while the 48 X 40 inch pallet is the workhorse in the United States, those dimensions don’t constitute an international standard; for example, the 800 X 1200 mm size is its counterpart throughout Europe. A major consideration for any company involved in the importing or exporting of goods on pallets (regardless of type) is the necessity to comply with ISPM (International Standards for Phytosanitary Measures) -15, which aims to prevent the spread of pests (insects) that damage plants (flora). Under that regulation, wood pallets must be treated either by heat or fumigation and evidenced with a certification symbol stenciled on the pallet.
Whichever the pallet type, competent suppliers are indispensible. Most pallet suppliers specialize in a specific type. One reason is the types of wood used; stringer pallets are typically made of hardwood (from deciduous trees) and block pallets are typically made from softwood (from coniferous trees). A pallet builder that utilizes one type of wood can’t switch to the other with overnight quickness. That’s because relationships with new sources have to be established and because the assembly of the two types are significantly different from one another as to require different work stations and different plant-layouts. A competent supplier is not only one that knows how to assemble a given type of pallet but does so in acknowledgement of the factors that affect product integrity (for example, the quality of lumber, the proper type and number of fasteners, etc.). Additionally, there’s a growing use of software in the designing of pallets.
A brandowner has to decide whether it wants to account for the number and whereabouts of pallets, and if so, whether it performs the accounting or outsources it to a pallet pooling/management company. That doesn’t rule out the possibility that the same brandowner might decide on a two-tier approach: one-trip pallets for international shipments but some type of accounting when channels are more local and closed-loop. CHEP is a pooling/management company that’s well-known for its block pallets, identifiable by their blue markings; however, there are other pooling/management companies that specialize in white pallets (the generic term for stringer pallets). Whether with block or stringer, friction between brandowner and pooling/management company can get contentious regarding responsibilities, placing a premium on a well-written contract.
Bearing the weight of sustainability
Dueling claims about what’s more sustainable are not only part of the competition between wood pallets and pallets of a different composition but also between stringer pallets and block pallets. More material goes into a block pallet; moreover, a block pallet is likely to weigh more (even with lighter-weight softwood). A block pallet is taller, making for additional clearance for fork insertion but utilizing more stacking space within transportation equipment. But whereas a stringer pallet might get points for material usage, lighter-weight, and space utilization, it is more prone to damage. Yes, fork-handling at times knocks a block askew (or even completely off); however, damage to notched stringers occurs more frequently because of the notching and the little lumber that remains between the top of the notch and the top of the stringer. If a damaged stringer pallet collapses, the loss of the inputs consumed by the load up to that point can be lost, more than countering the savings incurred in the aforementioned areas. It all underscores the fact that determining one material’s (or design’s) sustainability vis-à-vis that of another is fraught with subjectivity.
Think carefully before choosing stringer or block pallets. Not every possible factor was covered, or even mentioned, in this article. But I hope enough factors were included to constitute, figuratively at least, a pallet load.
Sterling Anthony is a consultant, specializing in the strategic use of marketing, logistics, and packaging. His contact information is: 100 Renaissance Center- P.O. Box 43176; Detroit, MI 48243; 313-531-1875 office; 313-531-1972 fax; [email protected]; www.pkgconsultant.com
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