ASTM D999 Standard Test Method for Vibration Testing of Shipping Containers states; “Shipping containers are exposed to complex dynamic stresses when subjected to vibration present in all transportation vehicles. Approximating the actual damage, or lack of damage, experienced in shipping may require subjecting the container(s) and contents to vibration inputs”. This can be very important for medical devices since these devices must be transported in the same environment that all products are distributed. Significant product and package responses and interactions during shipment can be severe and may lead to package or product failure. Identification of critical frequencies and the nature of package stresses can aid in minimizing the effect of these occurrences.
Exposure to vibration can affect the shipping container, its interior packaging, means of closure, and contents. These tests allow analysis of the interaction of these components. Design modification to one or more of these components may be utilized to achieve optimum performance in the shipping environment.
There are optional methods available to satisfy this segment of the package validation process. First, the package could be tested by simply shipping it to a destination using the anticipated shipping mode (ie. overnight parcel, common carrier etc.). This method, although economical, does not lend itself to a high degree of control and repeatability. Nor does it provide a statistically significant sampling of the product under evaluation.
Alternatively, laboratory simulations provide a means of subjecting packages to the anticipated distribution hazards of shock, vibration and dynamic compression in a controlled and repeatable manner. Observations of the package performance, as it is subjected to various hazards, can be accomplished in the laboratory and corrective action can be taken to alleviate any anticipated problems in a timely fashion.
Laboratory methods can be performed using standardized laboratory simulations such as ASTM D4169 “Performance Testing of Shipping Containers and Systems”, or International Safe Transit (ISTA) procedures like Procedure 1A, 2A or 3A. More information on the ISTA standards can be found at the ISTA website (www.ista.org).
The standardized laboratory procedures sequence a number of distribution “Elements” or dynamic tests that use realistic test intensity levels. The ASTM method also allows the user who has significant knowledge of his or her distribution system to design a test sequence which more closely matches a specific shipping environment. This may allow for a laboratory simulation based on actual field measurements including, vibration, drops, temperature and humidity and atmospheric pressure.
The most commonly used standardized distribution simulation test for medical device package validation is ASTM D4169, Distribution Cycle #13. This method is designed for packages weighing less than 100 pounds and transported by air and motor freight (small parcel distribution system.). This test “provides a uniform basis of evaluating in the laboratory, the ability of shipping units to withstand the distribution environment. This is accomplished by subjecting the packages to a test plan consisting of a sequence of anticipated hazard elements encountered in the chosen distribution environment.” A new method that has incorporated specific field data from the small parcel delivery system (e.g. UPS, FedEx, DHL, etc.) has been published by ASTM and is entitled; ASTM D7386-16 “Standard Practice for Performance Testing of Packages for Single Parcel Delivery Systems” . This may have more realistic standardized simulation elements for the small parcel distribution environment, however current early use of it in a laboratory setting has found it to be a very robust test for medical device packages and systems. The introduction of this standard and the ISTA 3A standard has caused some uncertainty in the medical device industry. Stay tuned for Part 4 in the series for a further explanation.