Investigation of Fundamental Relationships to Improve the Sustainability of Unit Loads
Sustainability is one of the most critical issues in today's packaging and supply chain industries. With the increase of environmental concerns, there has been a tremendous effort to improve packaging sustainability. However, most of these works have focused on individual packaging components rather than an integrated unit load. In global supply chains, three levels of packaging components (primary, secondary, and tertiary) are commonly assembled in the unit load form to facilitate efficient and economical storage and transport of goods to customers. Unit loads is important to improved, packaging sustainability.
This study developed the fundamental information that facilitates understanding and enhanced sustainability of unit loads from two different perspectives: physical interactions and end-of-life options of unit load components. From the physical interaction perspective, the effects of various characteristics of secondary and tertiary packaging components on load-bridging within unit loads are investigated.. Packaging component characteristics investigated included the flute type and size of corrugated paperboard boxes, stretch wrap containment force, and pallet stiffness. From the end-of-life option perspective, process methods and environmental impacts of wood pallet repair in the United States are analyzed to provide fundamental information for accurate life cycle assessment of pallets.
The experimental results of this study demonstrate that the size of corrugated paperboard boxes and stretch wrap containment force significantly affected the bridging of loads on pallets. The results regarding load-bridging, verified in this study, provides essential knowledge regarding factors influencing unit load deflection. Pallet design procedure should include the load-bridging effect. For simulated pallets which was comparable to a stringer class wood pallet spanning the width of a storage rack, average deflection in the unit load decreased by 70% when package size increased to 20 in. x 10 in. x 10 in. from 5 in. x 10 in. x 10 in. In addition, average deflection in the unit load consisting of 5 in. x 10 in. x 10 in. packages decreased by 50% when stretch wrap containment force increased to 30 lbs. from zero pounds. Updated design methods that consider the effect of packaging characteristics on unit load deflection can help to reduce the amount of raw materials required to build pallets using current pallet design methodologies.
The life cycle inventory analysis results of this study determined that pallet repair is an environmentally beneficial end-of-life option for 48 by 40- inch stringer class wood pallets in terms of greenhouse gas generation. Most wood pallet repair firms in the United States utilized high levels of manual labor with non-automated machinery support. The life cycle inventory results from this study can be a useful resource for researchers as an input to the life cycle assessment.