ASTM D4332 has been recently revised with changes more editorial than affecting the parameters. The practice’s main update is the following statement: “Environmental conditioning atmospheres can be used for testing packages with high moisture sensitivity and for testing packages with limited or no moisture sensitivity.” This statement does not provide insight into selecting temperature and humidity conditions. This also leads into questions regarding how to choose the conditions and the duration. Let’s take a minute and review this practice.
• First and foremost, this practice is NOT a simulation; it does not simulate any specific environment during transportation. A simulation would be more characteristic of actual conditions and would not dwell long enough to reach equilibrium.
• The practice is a stimulation, where the package and the product are subjected to conditions and allowed to reach equilibrium. This helps identify any issues related to the conditions selected.
• Since we cannot test for all conditions, the idea is to subject the items under test to conditions typically found in the distribution environment and then dwell at that temperature until equilibrium is attained. The packages should then be removed from the conditions and immediately subjected to further testing.
• The practice offers seven conditions commonly found in the distribution environment for consideration if environmental conditions are unknown.
• If unknown, the duration to attain equilibrium at the selected condition is a 72-hour dwell. When selecting a duration, consider the thermal mass of the package system.
• For corrugated materials, tropical environments significantly reduce the strength of the material; therefore, one may want to subject the package system to this type of environment.
• Medical devices and pharmaceuticals may want to select three or more environments as regulatory bodies will want to see the packages subjected to various conditions.
• Food companies that need to keep products cold may also be interested in a refrigerated environment with high humidity, reducing the strength of the packaging material.
As you can see, there are many things to consider when determining the conditions you want to use. Feel free to give us a call if you need some guidance. With over 100 chambers across both laboratories, we can replicate conditions at both extremes and everything in between.