Evaluation of Stability of Unit Loads for Tilt and Shock Events During Distribution

Initiatives to lightweight and reduce packaging materials to achieve sustainability goals have created unit load stability challenges in the transportation and handling of palletized packaged goods. Consequently, an increased focus is being placed on evaluating how current pre-shipment performance tests evaluate load stability. This study was undertaken to address the current need for establishing test methodologies towards observing a unit load’s overall stability during transportation and handling related activities commonly experienced in the distribution environment. With this goal, this study developed two test methods as well as apparatus/measuring tool to observe a palletized load’s overall stability. The experimentation involved unit loads of bottled water assembled using two commonly used stacking and stretch wrap patterns. Testing conditions for existing test procedures as well as personnel safety issues during testing were also considered and all tests were conducted in triplicate. The test methods developed included a “tilt test” which was designed to replicate the gravitational forces exerted on the unit load and an “incline impact test” designed to replicate the effect of short duration shocks experienced by unit loads. Collectively, the two test methods provide valuable test procedures and insight towards understanding a unit load’s response to shocks and shifts commonly experienced during distribution related activities. The data collected from these tests should contribute to potential revisions for International Safe Transit Association’s (ISTA) Procedures 3B and 3E testing requirements. Packaging engineers should be able to appropriately develop and/or validate unit loads of packaged goods utilizing the new test methods