ASTM F392/F392M-21

5.1?This practice is valuable in determining the resistance of flexible packaging materials to flex-formed pinhole failures. Conditioning levels A, B, or C are typically used. Reference Practice E171 and Guide F2097.

5.2?Conditioning D and E are typically used for determining the effect of flexing on barrier properties transmission rates related to gas and/or moisture.

5.3?This practice does not measure or condition materials for abrasion related to flex failure.

5.4?Failures in the integrity of one or more of the plies of a multi-ply structure may require alternative testing. Supplementary permeation testing using gas or water vapor can be used in conjunction with the flex test to measure the loss of ply integrity. Other test methods may be used after flexing for assessment of presence of pinholes. For a list of test methods, refer to Guide F2097.

1.1?This practice covers conditioning of flexible barrier materials for the determination of flex resistance. Subsequent testing can be performed to determine the effects of flexing on material properties. These tests are beyond the scope of this practice.

1.2?The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

1.3?This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.4?This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.