by Sterling Anthony, CPP, expert witness, packaging, warnings, patent infringement, cargo loading & securement, insurance claims
Pallets carry 95% of the world’s cargo, and 90% of pallets are constructed of wood. Those overwhelming percentages establish wood pallets as the linchpin of logistics, affecting the cost, efficiency, and safety with which transportation, material handling, and storage are performed.
The pallet, on surface, is a simple concept, a platform on which items are placed, allowing the now palletized load to be moved mechanically, such as with a forklift truck. On the other hand, pallets should be engineered, designed for structural integrity, under all reasonably-foreseeable conditions encountered from the time they’re loaded until the time they’re unloaded.
Pallets need to embody the requisite combination of strength, stiffness, durability, functionality/compatibility, and affordability.
Strength refers to load-bearing capacity.
Stiffness refers to resistance to undue bending and flexing.
Durability (if not designed for just one trip) refers to the ability to give service across multiple trips.
Functionality/compatibility refers to being consistent with the materials loaded, material handling equipment, transportation regulations, etc.
Affordability refers to FIRST that the pallet be fit for its intended purposes and THEN that it be attainable at the lowest comparable price.
Pallets are of two design categories, referring to how the base is constructed: stringer and block. A block pallet is 4-way, meaning that material handling forks can enter from 4 directions (front, back, and ends). A stringer pallet is 2-way (ends) but can be made 4-way with spaced notches for fork entry, but at the sacrifice of weakening the pallet and making it more vulnerable to damage.
Regardless of design, pallets are different than mass-produced items that (barring a manufacturing defect) are indistinguishable, one from the other. More so than being manufactured, pallets can be said to be assembled and crafted; therefore, there is an inherent potential for variation, even across pallets built from the same design. Some factors that can contribute to said variation include:
Lumber. A pallet’s physical properties are influenced by the type of wood, that is to say, whether hardwood (from deciduous trees) or softwoods (from coniferous trees). Within any one type of lumber are grades, reflecting how free the lumber is from such defects as bark, knotholes, and dimensional irregularities. Yet another important consideration is the degree to which the lumber has been kiln-dried or remains green.
Number and positioning of deck boards. A deck comprised of abutting boards, with no spaces in between——all other things being equal——is sturdier than a deck with spaced boards. Of the latter type of decks, the greater the spacing the less sturdy and the greater the opportunity of an unstable load.
Type, number, and positioning of fasteners. Whether staples or nails are used affect how well the components remain attached, and within each category of fasteners, there are different sizes, with different holding strengths. How many fasteners are used affects how steadfastly the components are joined. Whether the fasteners are patterned in a straight line or staggered not only has an effect on holding strength but also on how likely a board, for example, might split.
By industry standards, any company that loads a pallet is responsible for the fitness of the pallet, and by extension, the fitness of the palletized load.
When pallets fail, the immediate consequence is that the load becomes dangerous to move, prone to tilting on the forks or even falling off. The danger to anyone in the vicinity hardly needs elaboration. Pallet failure also can occur during storage, with the sudden collapse of the load. Failure also can occur during transportation making the unloading——and even the opening of the doors of the equipment——hazardous.
When pallet failure causes or contributes to cargo lost or personal injury and litigation ensues, either party would be wise to retain an expert. The expert should have knowledge of, and experience in, the design, specification, sourcing, inspection, and care of pallets.
Sterling Anthony, CPP, is a consultant to the industrial, institutional, and government sectors and an expert to the legal community. He is a former manager at Fortune 100 companies and a former instructor at two major universities. His contact information is: 100 Renaissance Center-Box 43176, Detroit, MI 48243; (office) 313-531-1875; (cell) 313-623-0522; (fax) 313-531-1972; thepackagingexpertwitness@gmail; www.thepackagingexpertwitness.com