ASTM C 1279 : 2023

1.1This test method covers the determination of edge stresses and surface stresses in annealed, heat-strengthened, and fully tempered flat glass products.

1.2This test method is non-destructive.

1.3This test method uses transmitted light and is, therefore, applicable to light-transmitting glasses.

1.4The test method is not applicable to chemically-tempered glass.

1.5Using the procedure described, surface stresses can be measured only on the “tin” side of float glass.

1.6Surface-stress measuring instruments are designed for a specific range of surface index of refraction.

1.7The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.8This 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.

1.9This 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.