This specification covers a perfluoroether elastomer in the form of molded rings.
This standard was revised to clearly specify the test methods to be followed during aromatic fuel resistance testing. The original standard presented elongation and tensile strength release limits with the test procedure allowing a 30 minute conditioning at room temperature prior to property measurement after 70 hours soaking in the aromatic fuel. This was in error, and the test procedure followed should have specified, "immediate deteriorated properties", and followed testing instructions as defined in D-471, Procedure for change in Volume. This change in conditioning procedure results in a re-specification of the elongation and tensile strength release requirements. The paragraph for defining hydraulic fluid resistance testing was corrected to read AS1241. The hours required for long term compression set testing was omitted in the original AMS 7254 and Footnote 2 was added to specify the frequency at which the fluid is to be replaced during testing.