By Rob Kaszubowski, CPP | Packaging Engineering Manager | Chainalytics
“Compression” and “stacking strength” are two terms often thrown around the packaging world as interchangeable references to the strength of a package or corrugated box.
But really, these two packaging performance measurements have totally separate functions. And one of them has the potential to significantly impact supply chain savings. Here’s how:
- Compression measures the potential strength of a box or package. It is calculated in a laboratory under a dynamic, moving load (typically at a rate of ½” per minute) at standard conditions (23°C with 50 percent relative humidity). The typical testing method uses a compression table and adheres to ASTM D-642 testing protocols.
- Stacking strength (or overall box performance), on the other hand, measures the size of load a box can endure during transport, storage and distribution. It’s tied to the many factors a package encounters throughout its journey, including pallet pattern layout, pallet quality, storage time, warehouse and transportation environmental conditions, mode of transportation, distance traveled and even the strength of the packaged product itself.
While stacking strength seems like the obvious measurement of choice, unfortunately it’s easier to write about it than to actually perform and implement stacking strength tests. The number of tests and length of time required to test true stacking strength are prohibitively expensive for many companies. The answer for some is to simply multiply their static load requirements by a “safety factor” to create a minimum lab compression requirement. But, considering that these factors can range from 2x up to 10x the dead load a box may see, this isn’t really the best practice.
How to Balance Packaging Material & Supply Chain Costs
If you truly want to design more effective packaging that strikes a balance between material and supply chain costs, try these practical exercises to figure out what strength you really require from your packaging:
- Measure and monitor your environmental conditions during storage and transport. (Don’t forget to factor in any seasonal swings, like increases in volume, storage or cross-docking requirements, changes in temperature/humidity, etc.!)
- Determine the amount of strength gained from product load sharing and consider whether the product inside your secondary packaging is strong enough to help support some of the load (for example, cereal cartons inside a shipper box).
- Review your pallet layout patterns to see if they are optimally designed for loading, storage and transport.
- Adjust your safety factors as you measure and monitor packaging and product damage.
- Evaluate the use of alternate test methods, such as dead load testing per ASTM D-4577.
Changes like these give you the freedom to downgrade or otherwise change packaging or storage materials and racking systems, increase stack heights or even change transportation modes. If your packaging optimization plans have remained static for several years, or your distribution environment has recently changed, now is the time to review your packaging performance requirements. Though a systematic change to your packaging optimization and engineering processes may require in-depth analysis, your potential savings will make it well worth the effort.
Rob Kaszubowski is a senior manager in Chainalytics Packaging Optimization competency, where he is focused on reducing product damage and implementing packaging cost savings initiatives.
