ASTM Addresses Distribution Simulation and Accelerated Aging
Standards updates aim for more-realistic testing.
ASTM Subcommittee F2.50 is clarifying the use of relative humidity levels in package accelerated-aging protocols to ensure more-realistic testing results. After three rounds of balloting on a revision to standard F1980-02, a fourth draft is being prepared that will be submitted to the subcommittee and full committee (F02) for concurrent voting, says Pat Nolan, chief operating officer, DDL (Eden Prairie, MN).
The revision is a new section, X3.0, advising that temperature and relative humidity values should be used to produce air-moisture content [absolute humidity] values closer to real-world conditions.
“Care should be exercised in using [relative] humidity levels that when combined with temperature produce moisture levels that may not be realistic in nature and may cause unnatural physical changes to materials. Absolute humidity should be maintained between the test temperature and realistic environments for the sterile barrier system life cycle,” the revision states.
“Protocols were being developed with excessive relative humidity that produced air-moisture content that was not representative or even close to being possible in the real world. It caused failures, such as delamination, that would not normally occur,” says Nolan.
X3.0 provides a table showing examples of the relative humidity that prevails at constant moisture content and variable temperatures.
|See Sidebar: ISO 11607 Changes|
The revision also excises a flow-chart showing all the conceptual components of a sterile-barrier shelf-life test plan. “The committee felt the flow-chart was beyond the scope of the standard, which is to provide guidance strictly on accelerated aging,” Nolan says.
Another element of package performance testing is undergoing revision in D10.21, a subcommittee of D10, of which Nolan is chairman. Under review is ASTM D4169, which describes distribution simulation testing (Standard Practice for Performance Testing of Shipping Containers and Systems). “The committee has identified a need to reduce the intensity of the random vibration test. The ballot is being worked up now. I don’t know what the random profile is going to look like, but the test intensity will be reduced at assurance Level 1 (the highest level of test intensity),” says Nolan.