3.1 This test method defines the thermal expansion of porcelain enamel and glaze frits by the interferometric method. This determination is critical in avoiding crazing (cracking) of these glass coatings due to mismatching of the thermal expansion between the coating and substrate materials.

1.1 This test method covers the interferometric determination of linear thermal expansion of premelted frits (porcelain enamel and glaze) and fired ceramic whiteware materials at temperatures lower than 1000°C (1830°F).

1.2 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.