1.1 This practice covers procedures for preparing and testing reference glass-to-metal bead-seals for determining the magnitude of thermal expansion (or contraction) mismatch between the glass and metal. Tests are in accordance with method F218 (2).

1.2 This practice applies to all glass-metal combinations, established or experimental, particularly those intended for electronic components.

1.3 The practical limit of the test in devising mismatch is approximately 300 ppm, above which the glass is likely to fracture.

1.4 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 and health practices and determine the applicability of regulatory limitations prior to use .